diff --git a/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java b/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java
index b6f42fa..07ba6a5 100644
--- a/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java
+++ b/src/main/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplate.java
@@ -53,8 +53,9 @@ public class RedisCacheEnhanceTemplate {
 
     public void set(String key, Object value, long ttlSeconds) {
         requirePositiveTtl(ttlSeconds);
-        redis.opsForValue().set(keyBuilder.build(key), codec.encode(value),
-                applyJitter(ttlSeconds), TimeUnit.SECONDS);
+        // 空值(写入空标记)按短 null-ttl 处理,与回源 null 一致,避免空标记长期占位
+        long ttl = (value == null) ? props.getNullTtlSeconds() : applyJitter(ttlSeconds);
+        redis.opsForValue().set(keyBuilder.build(key), codec.encode(value), ttl, TimeUnit.SECONDS);
     }
 
     // ---- 读 ----
diff --git a/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java b/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java
index 6f4ab8c..093293e 100644
--- a/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java
+++ b/src/test/java/com/njcn/middle/cache/template/RedisCacheEnhanceTemplateTest.java
@@ -339,4 +339,14 @@ class RedisCacheEnhanceTemplateTest {
         when(valueOps.get("cache:user:1")).thenReturn(null);
         assertFalse(template.exists("user:1"));
     }
+
+    // ---- #9: 公共 set(key,null) 用短 null-ttl(与回源空值一致) ----
+
+    @Test
+    void setNullUsesNullTtlNotDataTtl() {
+        props.setJitterRatio(0);
+        template.set("user:1", null, 3600); // 传入数据 TTL,但写空标记应改用短 null-ttl
+        verify(valueOps).set("cache:user:1", CacheConstant.NULL_SENTINEL,
+                props.getNullTtlSeconds(), TimeUnit.SECONDS);
+    }
 }