diff --git a/rt-thread-version/rt-thread-standard/programming-manual/device/crypto/crypto.md b/rt-thread-version/rt-thread-standard/programming-manual/device/crypto/crypto.md
index b8e4de37896de78f2af582a2cf4982f6dc97156d..1c8fb8248a16cf37da07c48dd8506c69549ad487 100644
--- a/rt-thread-version/rt-thread-standard/programming-manual/device/crypto/crypto.md
+++ b/rt-thread-version/rt-thread-standard/programming-manual/device/crypto/crypto.md
@@ -965,6 +965,8 @@ rt_uint32_t rt_hwcrypto_rng_update(void);
 例如检测随机数产生 1000，000 次，统计产生奇数与偶数的数量，代码如下：
 
 ```c
+#include <hw_rng.h>
+
 void hw_rng(void)
 {
     rt_uint32_t result=0;