diff --git a/api/core/app/apps/advanced_chat/app_runner.py b/api/core/app/apps/advanced_chat/app_runner.py
index 87493f1288..dbc42cc7bb 100644
--- a/api/core/app/apps/advanced_chat/app_runner.py
+++ b/api/core/app/apps/advanced_chat/app_runner.py
@@ -464,7 +464,7 @@ class AdvancedChatAppRunner(WorkflowBasedAppRunner):
                 if not node_id:
                     logger.warning("Memory block %s has no node_id, skip.", memory.spec.id)
                     continue
-                key = f"{node_id}.{memory.spec.id}"
+                key = f"{node_id}_{memory.spec.id}"
                 memory_blocks_dict[key] = memory.value
 
         return memory_blocks_dict
diff --git a/api/services/chatflow_memory_service.py b/api/services/chatflow_memory_service.py
index 982464b4ba..72a4fedac8 100644
--- a/api/services/chatflow_memory_service.py
+++ b/api/services/chatflow_memory_service.py
@@ -105,7 +105,7 @@ class ChatflowMemoryService:
 
     @staticmethod
     def save_memory(memory: MemoryBlock, variable_pool: VariablePool, is_draft: bool) -> None:
-        key = f"{memory.node_id}.{memory.spec.id}" if memory.node_id else memory.spec.id
+        key = f"{memory.node_id}_{memory.spec.id}" if memory.node_id else memory.spec.id
         variable_pool.add([MEMORY_BLOCK_VARIABLE_NODE_ID, key], memory.value)
         if memory.created_by.account_id:
             created_by_role = CreatorUserRole.ACCOUNT
@@ -139,7 +139,7 @@ class ChatflowMemoryService:
         if is_draft:
             with Session(bind=db.engine) as session:
                 draft_var_service = WorkflowDraftVariableService(session)
-                memory_selector = memory.spec.id if not memory.node_id else f"{memory.node_id}.{memory.spec.id}"
+                memory_selector = memory.spec.id if not memory.node_id else f"{memory.node_id}_{memory.spec.id}"
                 existing_vars = draft_var_service.get_draft_variables_by_selectors(
                     app_id=memory.app_id,
                     selectors=[[MEMORY_BLOCK_VARIABLE_NODE_ID, memory_selector]]
diff --git a/api/services/workflow_service.py b/api/services/workflow_service.py
index 91266b8869..667736b1ed 100644
--- a/api/services/workflow_service.py
+++ b/api/services/workflow_service.py
@@ -1086,6 +1086,6 @@ def _fetch_memory_blocks(
         if memory.spec.scope == MemoryScope.APP:
             memory_blocks[memory.spec.id] = memory.value
         else:  # NODE scope
-            memory_blocks[f"{memory.node_id}.{memory.spec.id}"] = memory.value
+            memory_blocks[f"{memory.node_id}_{memory.spec.id}"] = memory.value
 
     return memory_blocks