diff --git a/apps/routers/variable.py b/apps/routers/variable.py
index ea1a22e0ff579aa8ead43f8bd7efa1f65ced7aa5..2e04e8adfa533a9428381a092c6c0e945ac28de0 100644
--- a/apps/routers/variable.py
+++ b/apps/routers/variable.py
@@ -98,8 +98,8 @@ async def _get_predecessor_node_variables(
                             updated_at=datetime.fromisoformat(var_data['updated_at'].replace('Z', '+00:00'))
                         )
                         
-                        # 创建变量对象，并附加缓存的节点信息
-                        variable = create_variable(metadata, var_data.get('value', ''))
+                        # 创建变量对象，并附加缓存的节点信息（使用None避免类型验证失败）
+                        variable = create_variable(metadata, var_data.get('value'))
                         
                         # 将节点信息附加到变量对象上（用于后续响应格式化）
                         if hasattr(variable, '_cache_data'):
@@ -995,8 +995,8 @@ async def _create_node_output_variables(node, user_sub: str) -> List:
                 updated_at=datetime.now(UTC)
             )
             
-            # 创建变量对象
-            variable = create_variable(metadata, "")  # 配置阶段的潜在变量，值为空
+            # 创建变量对象（使用None作为默认值，避免类型验证失败）
+            variable = create_variable(metadata, None)  # 配置阶段的潜在变量，值为None
             variables.append(variable)
         
         logger.info(f"为节点 {node_id} 创建了 {len(variables)} 个输出变量: {[v.name for v in variables]}")
diff --git a/apps/scheduler/variable/base.py b/apps/scheduler/variable/base.py
index 94beaaebc0f084c1a5dbec6696f7b233a5d66154..a038e8439d67b6a4d4f0c97b24c98ebbbc95334d 100644
--- a/apps/scheduler/variable/base.py
+++ b/apps/scheduler/variable/base.py
@@ -82,9 +82,11 @@ class BaseVariable(ABC):
         if self.scope == VariableScope.SYSTEM and not getattr(self, '_initializing', False):
             raise ValueError("系统级变量不能修改")
         
-        # 验证类型
-        if not self._validate_type(new_value):
-            raise TypeError(f"变量 {self.name} 的值类型不匹配，期望: {self.var_type}")
+        # 对于None值，跳过类型验证（允许任意类型的变量设置为None）
+        if new_value is not None:
+            # 验证类型
+            if not self._validate_type(new_value):
+                raise TypeError(f"变量 {self.name} 的值类型不匹配，期望: {self.var_type}")
         
         self._value = new_value
         self.metadata.updated_at = datetime.now(UTC)
diff --git a/apps/services/predecessor_cache_service.py b/apps/services/predecessor_cache_service.py
index b300e07560a22d10ac10e3ef86125f40f9026378..0e88c6bd3527529a05726f670644fc3e77281893 100644
--- a/apps/services/predecessor_cache_service.py
+++ b/apps/services/predecessor_cache_service.py
@@ -491,7 +491,7 @@ class PredecessorCacheService:
                     'name': f"{node_id}.{param_name}",
                     'var_type': var_type.value,
                     'scope': VariableScope.CONVERSATION.value,
-                    'value': "",  # 配置阶段的潜在变量，值为空
+                    'value': None,  # 配置阶段的潜在变量，值为None
                     'description': description or f"来自节点 {node_id} 的输出参数 {param_name}",
                     'created_at': datetime.now(UTC).isoformat(),
                     'updated_at': datetime.now(UTC).isoformat(),