diff --git a/app/src/main/java/io/legado/app/data/entities/BaseSource.kt b/app/src/main/java/io/legado/app/data/entities/BaseSource.kt
index f9521c0d4..8ada19d69 100644
--- a/app/src/main/java/io/legado/app/data/entities/BaseSource.kt
+++ b/app/src/main/java/io/legado/app/data/entities/BaseSource.kt
@@ -179,6 +179,10 @@ interface BaseSource : JsExtensions {
         CacheManager.delete("userInfo_${getKey()}")
     }
 
+    /**
+     * 设置自定义变量
+     * @param variable 变量内容
+     */
     fun setVariable(variable: String?) {
         if (variable != null) {
             CacheManager.put("sourceVariable_${getKey()}", variable)
@@ -187,6 +191,9 @@ interface BaseSource : JsExtensions {
         }
     }
 
+    /**
+     * 获取自定义变量
+     */
     fun getVariable(): String? {
         return CacheManager.get("sourceVariable_${getKey()}")
     }
diff --git a/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt b/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt
index 7177f6a74..eaec99222 100644
--- a/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt
+++ b/app/src/main/java/io/legado/app/model/analyzeRule/RuleDataInterface.kt
@@ -8,7 +8,7 @@ interface RuleDataInterface {
         return when {
             value == null -> {
                 variableMap.remove(key)
-                putBigVariable(key, value)
+                putBigVariable(key, null)
                 true
             }
             value.length < 10000 -> {