diff --git a/backend/app/main_graph/nodes/react_nodes.py b/backend/app/main_graph/nodes/react_nodes.py
index b0338c0..2843aa1 100644
--- a/backend/app/main_graph/nodes/react_nodes.py
+++ b/backend/app/main_graph/nodes/react_nodes.py
@@ -88,7 +88,61 @@ def react_reason_node(state: MainGraphState) -> MainGraphState:
     return state
 
 
-# ========== 2. 错误处理节点 ==========
+# ========== 2. 联网搜索节点 ==========
+
+def web_search_node(state: MainGraphState) -> MainGraphState:
+    """
+    联网搜索节点：执行搜索并将结果保存到状态
+    """
+    state.current_phase = "web_searching"
+    
+    # 获取搜索查询
+    reasoning_result = state.debug_info.get("reasoning_result")
+    search_query = reasoning_result.metadata.get("search_query", state.user_query) if reasoning_result else state.user_query
+    
+    try:
+        from app.core import web_search
+        
+        print(f"[WebSearch] 搜索: {search_query}")
+        search_result = web_search(search_query, max_results=5)
+        
+        # 保存搜索结果到状态
+        if not hasattr(state, "web_search_results"):
+            state.web_search_results = []
+        state.web_search_results.append(search_result)
+        
+        # 将搜索结果添加到 rag_context，供 LLM 使用
+        if state.rag_context:
+            state.rag_context = f"{state.rag_context}\n\n---\n\n## 🌐 联网搜索结果:\n{search_result}"
+        else:
+            state.rag_context = f"## 🌐 联网搜索结果:\n{search_result}"
+        
+        state.success = True
+        print(f"[WebSearch] 搜索完成")
+        
+    except Exception as e:
+        from app.main_graph.state import ErrorRecord, ErrorSeverity
+        from datetime import datetime
+        
+        error_record = ErrorRecord(
+            error_type="WebSearchError",
+            error_message=str(e),
+            severity=ErrorSeverity.WARNING,
+            source="web_search_node",
+            timestamp=datetime.now().isoformat(),
+            retry_count=0,
+            max_retries=2,
+            context={"search_query": search_query}
+        )
+        state.errors.append(error_record)
+        state.current_error = error_record
+        state.current_phase = "error_handling"
+        state.success = False
+    
+    return state
+
+
+# ========== 3. 错误处理节点 ==========
 
 def error_handling_node(state: MainGraphState) -> MainGraphState:
     """
@@ -276,6 +330,7 @@ def route_by_reasoning(state: MainGraphState) -> str:
         "direct_response": "final_response",
         "retrieve_rag": "rag_retrieve",
         "re_retrieve_rag": "rag_retrieve",
+        "web_search": "web_search",  # ⭐ 新增：联网搜索
         "clarify": "final_response",
         "call_tool": "final_response",  # 暂时映射到 final_response，后续可以扩展
         "contact": "contact_subgraph",
@@ -291,6 +346,7 @@ def route_by_reasoning(state: MainGraphState) -> str:
 __all__ = [
     "init_state_node",
     "react_reason_node",
+    "web_search_node",  # ⭐ 新增
     "error_handling_node",
     "final_response_node",
     "route_by_reasoning"
diff --git a/backend/app/main_graph/state.py b/backend/app/main_graph/state.py
index eee414e..ed08255 100644
--- a/backend/app/main_graph/state.py
+++ b/backend/app/main_graph/state.py
@@ -88,6 +88,9 @@ class MainGraphState:
     rag_retrieved: bool = False  # 是否已经检索过
     rag_docs: List[Dict[str, Any]] = field(default_factory=list)  # 检索到的文档
     
+    # ========== 联网搜索相关字段 ⭐ 新增 ==========
+    web_search_results: List[str] = field(default_factory=list)  # 联网搜索结果
+    
     # ========== 错误处理字段 ==========
     errors: List[ErrorRecord] = field(default_factory=list)  # 错误列表
     current_error: Optional[ErrorRecord] = None  # 当前错误
diff --git a/backend/app/main_graph/utils/subgraph_builder.py b/backend/app/main_graph/utils/subgraph_builder.py
index 9d3868f..9df544f 100644
--- a/backend/app/main_graph/utils/subgraph_builder.py
+++ b/backend/app/main_graph/utils/subgraph_builder.py
@@ -10,6 +10,7 @@ from app.main_graph.state import MainGraphState, CurrentAction
 from .react_nodes import (
     init_state_node,
     react_reason_node,
+    web_search_node,  # ⭐ 新增
     error_handling_node,
     final_response_node,
     route_by_reasoning
@@ -109,10 +110,13 @@ def build_react_main_graph() -> StateGraph:
     # 3. RAG 检索节点
     graph.add_node("rag_retrieve", rag_retrieve_node)
     
-    # 4. 错误处理节点
+    # 4. 联网搜索节点 ⭐ 新增
+    graph.add_node("web_search", web_search_node)
+    
+    # 5. 错误处理节点
     graph.add_node("handle_error", error_handling_node)
     
-    # 5. 最终回答节点
+    # 6. 最终回答节点
     graph.add_node("final_response", final_response_node)
     
     # ========== 添加子图节点 ==========
@@ -151,6 +155,9 @@ def build_react_main_graph() -> StateGraph:
             # 检索分支 → 检索后回到推理
             "rag_retrieve": "rag_retrieve",
             
+            # 联网搜索分支 ⭐ 新增
+            "web_search": "web_search",
+            
             # 子图分支 → 子图后回到推理
             "contact_subgraph": "contact_subgraph",
             "dictionary_subgraph": "dictionary_subgraph",
@@ -164,8 +171,9 @@ def build_react_main_graph() -> StateGraph:
         }
     )
     
-    # 4. 循环边：检索/子图/错误处理 后 → 回到推理
+    # 4. 循环边：检索/搜索/子图/错误处理 后 → 回到推理
     graph.add_edge("rag_retrieve", "react_reason")
+    graph.add_edge("web_search", "react_reason")  # ⭐ 新增
     graph.add_edge("contact_subgraph", "react_reason")
     graph.add_edge("dictionary_subgraph", "react_reason")
     graph.add_edge("news_analysis_subgraph", "react_reason")
diff --git a/requirement.txt b/requirement.txt
index ae0a3a5..a9d522a 100644
--- a/requirement.txt
+++ b/requirement.txt
@@ -43,4 +43,5 @@ pypdf==6.10.0
 beautifulsoup4==4.14.3
 lxml==6.1.0
 pandas==3.0.2        # 若需Excel保留，否则移除
-spacy==3.8.14         # unstructured 可能依赖
\ No newline at end of file
+spacy==3.8.14         # unstructured 可能依赖
+duckduckgo-search>=6.0.0  # 联网搜索
\ No newline at end of file