diff --git a/docs/zh/api.md b/docs/zh/api.md
index 299b96f..e3dd052 100644
--- a/docs/zh/api.md
+++ b/docs/zh/api.md
@@ -77,8 +77,8 @@ FlashErrCode flash_set_env(const char *key, const char *value)
 FlashErrCode flash_save_env(void)
 ```
 
-#### 1.2.6 恢复环境变量
-将内存中的环境变量表恢复为默认值。
+#### 1.2.6 重置环境变量
+将内存中的环境变量表重置为默认值。
 
 ```C
 FlashErrCode flash_env_set_default(void)
diff --git a/flash/src/flash_env.c b/flash/src/flash_env.c
index 6d6e2d5..5d1d96f 100644
--- a/flash/src/flash_env.c
+++ b/flash/src/flash_env.c
@@ -394,7 +394,7 @@ FlashErrCode flash_del_env(const char *key){
 }
 
 /**
- * Set an environment variable. If it value is NULL, delete it.
+ * Set an environment variable. If it value is empty, delete it.
  * If not find it in environment variables table, then create it.
  *
  * @param key environment variable name
@@ -407,7 +407,7 @@ FlashErrCode flash_set_env(const char *key, const char *value) {
 
     FLASH_ASSERT(env_cache);
 
-    /* if value is null, delete it */
+    /* if ENV value is empty, delete it */
     if (*value == NULL) {
         result = flash_del_env(key);
     } else {
diff --git a/flash/src/flash_env_wl.c b/flash/src/flash_env_wl.c
index 93d84eb..ed39c66 100644
--- a/flash/src/flash_env_wl.c
+++ b/flash/src/flash_env_wl.c
@@ -427,7 +427,7 @@ FlashErrCode flash_del_env(const char *key){
 }
 
 /**
- * Set an environment variable. If it value is NULL, delete it.
+ * Set an environment variable. If it value is empty, delete it.
  * If not find it in environment variables table, then create it.
  *
  * @param key environment variable name
@@ -440,7 +440,7 @@ FlashErrCode flash_set_env(const char *key, const char *value) {
 
     FLASH_ASSERT(env_cache);
 
-    /* if value is null, delete it */
+    /* if ENV value is empty, delete it */
     if (*value == NULL) {
         result = flash_del_env(key);
     } else {