diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_flash/drv_flash_f4.c b/bsp/stm32/libraries/HAL_Drivers/drv_flash/drv_flash_f4.c
index 9e308d45ac..c1dc8284a7 100644
--- a/bsp/stm32/libraries/HAL_Drivers/drv_flash/drv_flash_f4.c
+++ b/bsp/stm32/libraries/HAL_Drivers/drv_flash/drv_flash_f4.c
@@ -373,9 +373,30 @@ static int fal_flash_erase_16k(long offset, size_t size);
 static int fal_flash_erase_64k(long offset, size_t size);
 static int fal_flash_erase_128k(long offset, size_t size);
 
-const struct fal_flash_dev stm32_onchip_flash_16k = { "onchip_flash_16k", STM32_FLASH_START_ADRESS_16K, FLASH_SIZE_GRANULARITY_16K, (16 * 1024), {NULL, fal_flash_read_16k, fal_flash_write_16k, fal_flash_erase_16k} };
-const struct fal_flash_dev stm32_onchip_flash_64k = { "onchip_flash_64k", STM32_FLASH_START_ADRESS_64K, FLASH_SIZE_GRANULARITY_64K, (64 * 1024), {NULL, fal_flash_read_64k, fal_flash_write_64k, fal_flash_erase_64k} };
-const struct fal_flash_dev stm32_onchip_flash_128k = { "onchip_flash_128k", STM32_FLASH_START_ADRESS_128K, FLASH_SIZE_GRANULARITY_128K, (128 * 1024), {NULL, fal_flash_read_128k, fal_flash_write_128k, fal_flash_erase_128k} };
+const struct fal_flash_dev stm32_onchip_flash_16k = {
+    "onchip_flash_16k",
+    STM32_FLASH_START_ADRESS_16K,
+    FLASH_SIZE_GRANULARITY_16K,
+    (16 * 1024),
+    {NULL, fal_flash_read_16k, fal_flash_write_16k, fal_flash_erase_16k},
+    8,
+};
+const struct fal_flash_dev stm32_onchip_flash_64k = {
+    "onchip_flash_64k",
+    STM32_FLASH_START_ADRESS_64K,
+    FLASH_SIZE_GRANULARITY_64K,
+    (64 * 1024),
+    {NULL, fal_flash_read_64k, fal_flash_write_64k, fal_flash_erase_64k},
+    8,
+};
+const struct fal_flash_dev stm32_onchip_flash_128k = {
+    "onchip_flash_128k",
+    STM32_FLASH_START_ADRESS_128K,
+    FLASH_SIZE_GRANULARITY_128K,
+    (128 * 1024),
+    {NULL, fal_flash_read_128k, fal_flash_write_128k, fal_flash_erase_128k},
+    8,
+};
 
 static int fal_flash_read_16k(long offset, rt_uint8_t *buf, size_t size)
 {
diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_gpio.c b/bsp/stm32/libraries/HAL_Drivers/drv_gpio.c
index ee06f26003..1bb7b9c170 100644
--- a/bsp/stm32/libraries/HAL_Drivers/drv_gpio.c
+++ b/bsp/stm32/libraries/HAL_Drivers/drv_gpio.c
@@ -159,7 +159,7 @@ static struct rt_pin_irq_hdr pin_irq_hdr_tab[] =
 };
 static uint32_t pin_irq_enable_mask = 0;
 
-#define ITEM_NUM(items) sizeof(items) / sizeof(items[0])
+#define ITEM_NUM(items) (sizeof(items) / sizeof(items[0]))
 
 static rt_base_t stm32_pin_get(const char *name)
 {
@@ -279,10 +279,10 @@ static void stm32_pin_mode(rt_device_t dev, rt_base_t pin, rt_base_t mode)
 
 rt_inline rt_int32_t bit2bitno(rt_uint32_t bit)
 {
-    rt_uint8_t i;
+    rt_int32_t i;
     for (i = 0; i < 32; i++)
     {
-        if ((0x01 << i) == bit)
+        if (((rt_uint32_t)0x01 << i) == bit)
         {
             return i;
         }
@@ -293,7 +293,7 @@ rt_inline rt_int32_t bit2bitno(rt_uint32_t bit)
 rt_inline const struct pin_irq_map *get_pin_irq_map(uint32_t pinbit)
 {
     rt_int32_t mapindex = bit2bitno(pinbit);
-    if (mapindex < 0 || mapindex >= ITEM_NUM(pin_irq_map))
+    if (mapindex < 0 || mapindex >= (rt_int32_t)ITEM_NUM(pin_irq_map))
     {
         return RT_NULL;
     }
@@ -312,7 +312,7 @@ static rt_err_t stm32_pin_attach_irq(struct rt_device *device, rt_int32_t pin,
     }
 
     irqindex = bit2bitno(PIN_STPIN(pin));
-    if (irqindex < 0 || irqindex >= ITEM_NUM(pin_irq_map))
+    if (irqindex < 0 || irqindex >= (rt_int32_t)ITEM_NUM(pin_irq_map))
     {
         return RT_ENOSYS;
     }
@@ -351,7 +351,7 @@ static rt_err_t stm32_pin_dettach_irq(struct rt_device *device, rt_int32_t pin)
     }
 
     irqindex = bit2bitno(PIN_STPIN(pin));
-    if (irqindex < 0 || irqindex >= ITEM_NUM(pin_irq_map))
+    if (irqindex < 0 || irqindex >= (rt_int32_t)ITEM_NUM(pin_irq_map))
     {
         return RT_ENOSYS;
     }
@@ -387,7 +387,7 @@ static rt_err_t stm32_pin_irq_enable(struct rt_device *device, rt_base_t pin,
     if (enabled == PIN_IRQ_ENABLE)
     {
         irqindex = bit2bitno(PIN_STPIN(pin));
-        if (irqindex < 0 || irqindex >= ITEM_NUM(pin_irq_map))
+        if (irqindex < 0 || irqindex >= (rt_int32_t)ITEM_NUM(pin_irq_map))
         {
             return RT_ENOSYS;
         }
@@ -497,7 +497,7 @@ static rt_err_t stm32_pin_irq_enable(struct rt_device *device, rt_base_t pin,
 
     return RT_EOK;
 }
-const static struct rt_pin_ops _stm32_pin_ops =
+static const struct rt_pin_ops _stm32_pin_ops =
 {
     stm32_pin_mode,
     stm32_pin_write,
diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_soft_i2c.c b/bsp/stm32/libraries/HAL_Drivers/drv_soft_i2c.c
index c284e3d965..144da38d48 100644
--- a/bsp/stm32/libraries/HAL_Drivers/drv_soft_i2c.c
+++ b/bsp/stm32/libraries/HAL_Drivers/drv_soft_i2c.c
@@ -198,7 +198,7 @@ int rt_hw_i2c_init(void)
     rt_size_t obj_num = sizeof(i2c_obj) / sizeof(struct stm32_i2c);
     rt_err_t result;
 
-    for (int i = 0; i < obj_num; i++)
+    for (rt_uint32_t i = 0; i < obj_num; i++)
     {
         i2c_obj[i].ops = stm32_bit_ops_default;
         i2c_obj[i].ops.data = (void*)&soft_i2c_config[i];
diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_spi.c b/bsp/stm32/libraries/HAL_Drivers/drv_spi.c
index 7630d39189..d8f6a00a8e 100644
--- a/bsp/stm32/libraries/HAL_Drivers/drv_spi.c
+++ b/bsp/stm32/libraries/HAL_Drivers/drv_spi.c
@@ -420,7 +420,7 @@ static const struct rt_spi_ops stm_spi_ops =
 static int rt_hw_spi_bus_init(void)
 {
     rt_err_t result;
-    for (int i = 0; i < sizeof(spi_config) / sizeof(spi_config[0]); i++)
+    for (rt_uint32_t i = 0; i < sizeof(spi_config) / sizeof(spi_config[0]); i++)
     {
         spi_bus_obj[i].config = &spi_config[i];
         spi_bus_obj[i].spi_bus.parent.user_data = &spi_config[i];
diff --git a/bsp/stm32/libraries/HAL_Drivers/drv_usart.c b/bsp/stm32/libraries/HAL_Drivers/drv_usart.c
index 6211676056..714cdee277 100644
--- a/bsp/stm32/libraries/HAL_Drivers/drv_usart.c
+++ b/bsp/stm32/libraries/HAL_Drivers/drv_usart.c
@@ -1132,7 +1132,7 @@ int rt_hw_usart_init(void)
 
     stm32_uart_get_dma_config();
 
-    for (int i = 0; i < obj_num; i++)
+    for (rt_uint32_t i = 0; i < obj_num; i++)
     {
         /* init UART object */
         uart_obj[i].config = &uart_config[i];
diff --git a/components/dfs/filesystems/romfs/dfs_romfs.c b/components/dfs/filesystems/romfs/dfs_romfs.c
index 9e355471a8..00831613c7 100644
--- a/components/dfs/filesystems/romfs/dfs_romfs.c
+++ b/components/dfs/filesystems/romfs/dfs_romfs.c
@@ -40,7 +40,7 @@ int dfs_romfs_ioctl(struct dfs_fd *file, int cmd, void *args)
 rt_inline int check_dirent(struct romfs_dirent *dirent)
 {
     if ((dirent->type != ROMFS_DIRENT_FILE && dirent->type != ROMFS_DIRENT_DIR)
-        || dirent->size == ~0)
+        || dirent->size == ~0U)
         return -1;
     return 0;
 }
@@ -84,7 +84,7 @@ struct romfs_dirent *dfs_romfs_lookup(struct romfs_dirent *root_dirent, const ch
         {
             if (check_dirent(&dirent[index]) != 0)
                 return NULL;
-            if (rt_strlen(dirent[index].name) == (subpath_end - subpath) &&
+            if (rt_strlen(dirent[index].name) == (rt_size_t)(subpath_end - subpath) &&
                     rt_strncmp(dirent[index].name, subpath, (subpath_end - subpath)) == 0)
             {
                 dirent_size = dirent[index].size;
@@ -157,7 +157,7 @@ int dfs_romfs_read(struct dfs_fd *file, void *buf, size_t count)
 
 int dfs_romfs_lseek(struct dfs_fd *file, off_t offset)
 {
-    if (offset <= file->size)
+    if (offset <= (off_t)file->size)
     {
         file->pos = offset;
         return file->pos;
@@ -261,7 +261,7 @@ int dfs_romfs_getdents(struct dfs_fd *file, struct dirent *dirp, uint32_t count)
         return -EINVAL;
 
     index = 0;
-    for (index = 0; index < count && file->pos < file->size; index ++)
+    for (index = 0; index < count && file->pos < (off_t)file->size; index ++)
     {
         d = dirp + index;
 
@@ -295,6 +295,7 @@ static const struct dfs_file_ops _rom_fops =
     NULL,
     dfs_romfs_lseek,
     dfs_romfs_getdents,
+    NULL,
 };
 static const struct dfs_filesystem_ops _romfs =
 {
diff --git a/components/dfs/filesystems/romfs/romfs.c b/components/dfs/filesystems/romfs/romfs.c
index 847fcc6e27..0895ece6c4 100644
--- a/components/dfs/filesystems/romfs/romfs.c
+++ b/components/dfs/filesystems/romfs/romfs.c
@@ -10,17 +10,16 @@
 #include <rtthread.h>
 #include <dfs_romfs.h>
 
-const static unsigned char _dummy_dummy_txt[] =
-{
-    0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x61, 0x20, 0x66, 0x69, 0x6c, 0x65, 0x21, 0x0d, 0x0a,
+static const unsigned char _dummy_dummy_txt[] = {
+    0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x61,
+    0x20, 0x66, 0x69, 0x6c, 0x65, 0x21, 0x0d, 0x0a,
 };
 
-const static struct romfs_dirent _dummy[] =
-{
+static const struct romfs_dirent _dummy[] = {
     {ROMFS_DIRENT_FILE, "dummy.txt", _dummy_dummy_txt, sizeof(_dummy_dummy_txt)},
 };
 
-const static unsigned char _dummy_txt[] =
+static const unsigned char _dummy_txt[] =
 {
     0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x61, 0x20, 0x66, 0x69, 0x6c, 0x65, 0x21, 0x0d, 0x0a,
 };
diff --git a/components/dfs/src/dfs.c b/components/dfs/src/dfs.c
index 23cac5c9e9..921ec1c115 100644
--- a/components/dfs/src/dfs.c
+++ b/components/dfs/src/dfs.c
@@ -132,7 +132,7 @@ static int fd_alloc(struct dfs_fdtable *fdt, int startfd)
     }
 
     /* allocate a larger FD container */
-    if (idx == fdt->maxfd && fdt->maxfd < DFS_FD_MAX)
+    if (idx == (int)fdt->maxfd && fdt->maxfd < DFS_FD_MAX)
     {
         int cnt, index;
         struct dfs_fd **fds;
@@ -145,7 +145,7 @@ static int fd_alloc(struct dfs_fdtable *fdt, int startfd)
         if (fds == NULL) goto __exit; /* return fdt->maxfd */
 
         /* clean the new allocated fds */
-        for (index = fdt->maxfd; index < cnt; index ++)
+        for (index = (int)fdt->maxfd; index < cnt; index ++)
         {
             fds[index] = NULL;
         }
@@ -186,7 +186,7 @@ int fd_new(void)
     idx = fd_alloc(fdt, 0);
 
     /* can't find an empty fd entry */
-    if (idx == fdt->maxfd)
+    if (idx == (int)fdt->maxfd)
     {
         idx = -(1 + DFS_FD_OFFSET);
         LOG_E("DFS fd new is failed! Could not found an empty fd entry.");
diff --git a/components/drivers/i2c/i2c-bit-ops.c b/components/drivers/i2c/i2c-bit-ops.c
index ae1f4db9c0..02e6d03720 100644
--- a/components/drivers/i2c/i2c-bit-ops.c
+++ b/components/drivers/i2c/i2c-bit-ops.c
@@ -372,7 +372,8 @@ static rt_size_t i2c_bit_xfer(struct rt_i2c_bus_device *bus,
 {
     struct rt_i2c_msg *msg;
     struct rt_i2c_bit_ops *ops = (struct rt_i2c_bit_ops *)bus->priv;
-    rt_int32_t i, ret;
+    rt_uint32_t i;
+    rt_int32_t ret;
     rt_uint16_t ignore_nack;
 
     if (num == 0) return 0;
@@ -404,7 +405,9 @@ static rt_size_t i2c_bit_xfer(struct rt_i2c_bus_device *bus,
         {
             ret = i2c_recv_bytes(bus, msg);
             if (ret >= 1)
+            {
                 LOG_D("read %d byte%s", ret, ret == 1 ? "" : "s");
+            }
             if (ret < msg->len)
             {
                 if (ret >= 0)
@@ -416,7 +419,9 @@ static rt_size_t i2c_bit_xfer(struct rt_i2c_bus_device *bus,
         {
             ret = i2c_send_bytes(bus, msg);
             if (ret >= 1)
+            {
                 LOG_D("write %d byte%s", ret, ret == 1 ? "" : "s");
+            }
             if (ret < msg->len)
             {
                 if (ret >= 0)
diff --git a/components/drivers/i2c/i2c_core.c b/components/drivers/i2c/i2c_core.c
index c629765f65..067b9219c1 100644
--- a/components/drivers/i2c/i2c_core.c
+++ b/components/drivers/i2c/i2c_core.c
@@ -108,7 +108,7 @@ rt_size_t rt_i2c_master_send(struct rt_i2c_bus_device *bus,
                              const rt_uint8_t         *buf,
                              rt_uint32_t               count)
 {
-    rt_err_t ret;
+    rt_size_t ret;
     struct rt_i2c_msg msg;
 
     msg.addr  = addr;
@@ -127,7 +127,7 @@ rt_size_t rt_i2c_master_recv(struct rt_i2c_bus_device *bus,
                              rt_uint8_t               *buf,
                              rt_uint32_t               count)
 {
-    rt_err_t ret;
+    rt_size_t ret;
     struct rt_i2c_msg msg;
     RT_ASSERT(bus != RT_NULL);
 
diff --git a/components/drivers/serial/serial.c b/components/drivers/serial/serial.c
index c749897a08..9eb7f64cc7 100644
--- a/components/drivers/serial/serial.c
+++ b/components/drivers/serial/serial.c
@@ -193,7 +193,7 @@ static int serial_fops_poll(struct dfs_fd *fd, struct rt_pollreq *req)
     return mask;
 }
 
-const static struct dfs_file_ops _serial_fops =
+static const struct dfs_file_ops _serial_fops =
 {
     serial_fops_open,
     serial_fops_close,
@@ -893,7 +893,7 @@ struct speed_baudrate_item
     int baudrate;
 };
 
-const static struct speed_baudrate_item _tbl[] =
+static const struct speed_baudrate_item _tbl[] =
 {
     {B2400, BAUD_RATE_2400},
     {B4800, BAUD_RATE_4800},
@@ -911,7 +911,7 @@ const static struct speed_baudrate_item _tbl[] =
 
 static speed_t _get_speed(int baudrate)
 {
-    int index;
+    rt_uint32_t index;
 
     for (index = 0; index < sizeof(_tbl)/sizeof(_tbl[0]); index ++)
     {
@@ -924,7 +924,7 @@ static speed_t _get_speed(int baudrate)
 
 static int _get_baudrate(speed_t speed)
 {
-    int index;
+    rt_uint32_t index;
 
     for (index = 0; index < sizeof(_tbl)/sizeof(_tbl[0]); index ++)
     {
diff --git a/components/fal/src/fal_rtt.c b/components/fal/src/fal_rtt.c
index 7747bff9e7..20925dab6f 100644
--- a/components/fal/src/fal_rtt.c
+++ b/components/fal/src/fal_rtt.c
@@ -264,7 +264,7 @@ static rt_err_t mtd_nor_dev_erase(struct rt_mtd_nor_device* device, rt_off_t off
 
     ret = fal_partition_erase(part->fal_part, offset, length);
 
-    if (ret != length)
+    if ((rt_uint32_t)ret != length)
     {
         return -RT_ERROR;
     }
@@ -556,7 +556,7 @@ static void fal(uint8_t argc, char **argv) {
 #define CMD_ERASE_INDEX               3
 #define CMD_BENCH_INDEX               4
 
-    int result;
+    int result = 0;
     static const struct fal_flash_dev *flash_dev = NULL;
     static const struct fal_partition *part_dev = NULL;
     size_t i = 0, j = 0;
@@ -875,7 +875,7 @@ static void fal(uint8_t argc, char **argv) {
                             result = fal_partition_read(part_dev, i, read_data, cur_op_size);
                         }
                         /* data check */
-                        for (int index = 0; index < cur_op_size; index ++)
+                        for (rt_uint32_t index = 0; index < cur_op_size; index ++)
                         {
                             if (write_data[index] != read_data[index])
                             {
diff --git a/components/libc/posix/io/poll/poll.c b/components/libc/posix/io/poll/poll.c
index ba2442c0d5..7d642e29e6 100644
--- a/components/libc/posix/io/poll/poll.c
+++ b/components/libc/posix/io/poll/poll.c
@@ -154,7 +154,7 @@ static int poll_do(struct pollfd *fds, nfds_t nfds, struct rt_poll_table *pt, in
 {
     int num;
     int istimeout = 0;
-    int n;
+    rt_uint32_t n;
     struct pollfd *pf;
     int  ret = 0;
 
diff --git a/components/net/netdev/src/netdev.c b/components/net/netdev/src/netdev.c
index f121f52c19..3cd637ce50 100644
--- a/components/net/netdev/src/netdev.c
+++ b/components/net/netdev/src/netdev.c
@@ -47,7 +47,7 @@ int netdev_register(struct netdev *netdev, const char *name, void *user_data)
 {
     rt_base_t level;
     uint16_t flags_mask;
-    int index;
+    rt_uint32_t index;
 
     RT_ASSERT(netdev);
     RT_ASSERT(name);
@@ -706,7 +706,7 @@ void netdev_low_level_set_gw(struct netdev *netdev, const ip_addr_t *gw)
  */
 void netdev_low_level_set_dns_server(struct netdev *netdev, uint8_t dns_num, const ip_addr_t *dns_server)
 {
-    int index;
+    uint32_t index;
 
     RT_ASSERT(dns_server);
 
@@ -1066,7 +1066,8 @@ int netdev_cmd_ping(char* target_name, char *netdev_name, rt_uint32_t times, rt_
 
     struct netdev *netdev = RT_NULL;
     struct netdev_ping_resp ping_resp;
-    int index, ret = 0;
+    uint32_t index;
+    int ret = 0;
 
     if (size == 0)
     {
@@ -1172,7 +1173,7 @@ MSH_CMD_EXPORT_ALIAS(netdev_ping, ping, ping network host);
 
 static void netdev_list_dns(void)
 {
-    int index = 0;
+    rt_uint32_t index = 0;
     struct netdev *netdev = RT_NULL;
     rt_slist_t *node  = RT_NULL;
 
diff --git a/components/net/sal/src/sal_socket.c b/components/net/sal/src/sal_socket.c
index 8f4ac915eb..831b41c3c7 100644
--- a/components/net/sal/src/sal_socket.c
+++ b/components/net/sal/src/sal_socket.c
@@ -158,7 +158,8 @@ static void check_netdev_internet_up_work(struct rt_work *work, void *work_data)
 #define SAL_INTERNET_MONTH_LEN 4
 #define SAL_INTERNET_DATE_LEN  16
 
-    int index, sockfd = -1, result = 0;
+    rt_uint32_t index;
+    int sockfd = -1, result = 0;
     struct sockaddr_in server_addr;
     struct hostent *host;
     struct timeval timeout;
@@ -168,7 +169,7 @@ static void check_netdev_internet_up_work(struct rt_work *work, void *work_data)
 
     const char month[][SAL_INTERNET_MONTH_LEN] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
     char date[SAL_INTERNET_DATE_LEN];
-    int moth_num = 0;
+    rt_uint32_t moth_num = 0;
 
     struct sal_proto_family *pf = (struct sal_proto_family *) netdev->sal_user_data;
     const struct sal_socket_ops *skt_ops;
@@ -376,7 +377,8 @@ static void sal_unlock(void)
  */
 int sal_netdev_cleanup(struct netdev *netdev)
 {
-    int idx = 0, find_dev;
+    uint32_t idx = 0;
+    int find_dev;
 
     do
     {
diff --git a/libcpu/arm/common/showmem.c b/libcpu/arm/common/showmem.c
index 1a94ff1d9f..e1081e0524 100644
--- a/libcpu/arm/common/showmem.c
+++ b/libcpu/arm/common/showmem.c
@@ -12,7 +12,7 @@
 
 void rt_hw_show_memory(rt_uint32_t addr, rt_uint32_t size)
 {
-    int i = 0, j =0;
+    rt_uint32_t i = 0, j =0;
 
     RT_ASSERT(addr);
 
diff --git a/src/kservice.c b/src/kservice.c
index 4d3aea6709..c59fd78578 100644
--- a/src/kservice.c
+++ b/src/kservice.c
@@ -247,7 +247,7 @@ RT_WEAK void *rt_memcpy(void *dst, const void *src, rt_ubase_t count)
     char *src_ptr = (char *)src;
     long *aligned_dst;
     long *aligned_src;
-    int len = count;
+    rt_ubase_t len = count;
 
     /* If the size is small, or either SRC or DST is unaligned,
     then punt into the byte copy loop.  This should be rare. */
diff --git a/src/mem.c b/src/mem.c
index f1e1eeba55..0be629fa37 100644
--- a/src/mem.c
+++ b/src/mem.c
@@ -290,10 +290,14 @@ void *rt_smem_alloc(rt_smem_t m, rt_size_t size)
     RT_ASSERT(rt_object_is_systemobject(&m->parent));
 
     if (size != RT_ALIGN(size, RT_ALIGN_SIZE))
+    {
         RT_DEBUG_LOG(RT_DEBUG_MEM, ("malloc size %d, but align to %d\n",
                                     size, RT_ALIGN(size, RT_ALIGN_SIZE)));
+    }
     else
+    {
         RT_DEBUG_LOG(RT_DEBUG_MEM, ("malloc size %d\n", size));
+    }
 
     small_mem = (struct rt_small_mem *)m;
     /* alignment size */
diff --git a/src/timer.c b/src/timer.c
index 1f048c9b09..148648ba64 100644
--- a/src/timer.c
+++ b/src/timer.c
@@ -820,7 +820,7 @@ static void _timer_thread_entry(void *parameter)
  */
 void rt_system_timer_init(void)
 {
-    int i;
+    rt_uint32_t i;
 
     for (i = 0; i < sizeof(_timer_list) / sizeof(_timer_list[0]); i++)
     {