diff --git a/src/blackboard/operations.py b/src/blackboard/operations.py
index 4714678..086e64d 100644
--- a/src/blackboard/operations.py
+++ b/src/blackboard/operations.py
@@ -185,6 +185,7 @@ class Blackboard:
 
     def list_tasks(self, status: Optional[str] = None,
                    assignee: Optional[str] = None,
+                   assigned_by: Optional[str] = None,
                    parent_task: Optional[str] = None) -> List[Task]:
         """列出任务"""
         conn = self._conn()
@@ -198,6 +199,9 @@ class Blackboard:
             if assignee:
                 conditions.append("assignee=?")
                 params.append(assignee)
+            if assigned_by:
+                conditions.append("assigned_by=?")
+                params.append(assigned_by)
             if parent_task is not None:
                 conditions.append("parent_task=?")
                 params.append(parent_task)