diff --git a/components/drivers/src/ringbuffer.c b/components/drivers/src/ringbuffer.c
index 3e76b1774ac2fc21f97c53c118be2685d1857e64..e33f533db096890227710977b1032ce5654e3a10 100644
--- a/components/drivers/src/ringbuffer.c
+++ b/components/drivers/src/ringbuffer.c
@@ -244,7 +244,7 @@ rt_size_t rt_ringbuffer_peak(struct rt_ringbuffer *rb, rt_uint8_t **ptr)
 
     *ptr = &rb->buffer_ptr[rb->read_index];
 
-    if(rb->buffer_size - rb->read_index > size)
+    if((rt_size_t)(rb->buffer_size - rb->read_index) > size)
     {
         rb->read_index += size;
         return size;
diff --git a/components/libc/compilers/common/time.c b/components/libc/compilers/common/time.c
index 24289088fb75b40a0c64e54dd4c138e1eb2ecea1..5bfff159142d97f9adc2b9fb62ba66c07af3d335 100644
--- a/components/libc/compilers/common/time.c
+++ b/components/libc/compilers/common/time.c
@@ -240,7 +240,7 @@ RTM_EXPORT(mktime);
 char* asctime_r(const struct tm *t, char *buf)
 {
     /* Checking input validity */
-    if (rt_strlen(days) <= (t->tm_wday << 2) || rt_strlen(months) <= (t->tm_mon << 2))
+    if ((int)rt_strlen(days) <= (t->tm_wday << 2) || (int)rt_strlen(months) <= (t->tm_mon << 2))
     {
         LOG_W("asctime_r: the input parameters exceeded the limit, please check it.");
         *(int*) buf = *(int*) days;