diff --git a/app/algorithms/valve_isolation.py b/app/algorithms/valve_isolation.py
index 98f22ce..092f4f8 100644
--- a/app/algorithms/valve_isolation.py
+++ b/app/algorithms/valve_isolation.py
@@ -1,7 +1,12 @@
 from collections import defaultdict, deque
 from typing import Any
 
-from app.services.tjnetwork import get_network_link_nodes
+from app.services.tjnetwork import (
+    get_network_link_nodes,
+    is_node,
+    is_link,
+    get_link_properties,
+)
 
 
 VALVE_LINK_TYPE = "valve"
@@ -30,6 +35,21 @@ def valve_isolation_analysis(
 
     start_nodes = set()
 
+    for element in target_elements:
+        if is_node(network, element):
+            start_nodes.add(element)
+        elif is_link(network, element):
+            link_props = get_link_properties(network, element)
+            node1 = link_props.get("node1")
+            node2 = link_props.get("node2")
+            if not node1 or not node2:
+                # 如果是批量处理，可以选择跳过错误或记录错误，这里暂时保持严谨抛出异常
+                raise ValueError(f"Accident link {element} missing node endpoints")
+            start_nodes.add(node1)
+            start_nodes.add(node2)
+        else:
+            raise ValueError(f"Accident element {element} not found")
+
     adjacency: dict[str, set[str]] = defaultdict(set)
     valve_links: dict[str, tuple[str, str]] = {}
     for link_entry in get_network_link_nodes(network):