diff --git a/lightrag/api/config.py b/lightrag/api/config.py
index 2e15fd3a..ad0e670b 100644
--- a/lightrag/api/config.py
+++ b/lightrag/api/config.py
@@ -244,6 +244,9 @@ def parse_args() -> argparse.Namespace:
     # Get MAX_PARALLEL_INSERT from environment
     args.max_parallel_insert = get_env_value("MAX_PARALLEL_INSERT", 2, int)
 
+    # Get MAX_GRAPH_NODES from environment
+    args.max_graph_nodes = get_env_value("MAX_GRAPH_NODES", 1000, int)
+
     # Handle openai-ollama special case
     if args.llm_binding == "openai-ollama":
         args.llm_binding = "openai"
diff --git a/lightrag/api/lightrag_server.py b/lightrag/api/lightrag_server.py
index 7a34ab5c..cd87af22 100644
--- a/lightrag/api/lightrag_server.py
+++ b/lightrag/api/lightrag_server.py
@@ -326,6 +326,7 @@ def create_app(args):
             enable_llm_cache=args.enable_llm_cache,
             auto_manage_storages_states=False,
             max_parallel_insert=args.max_parallel_insert,
+            max_graph_nodes=args.max_graph_nodes,
             addon_params={"language": args.summary_language},
         )
     else:  # azure_openai
@@ -353,6 +354,7 @@ def create_app(args):
             enable_llm_cache=args.enable_llm_cache,
             auto_manage_storages_states=False,
             max_parallel_insert=args.max_parallel_insert,
+            max_graph_nodes=args.max_graph_nodes,
             addon_params={"language": args.summary_language},
         )
 
@@ -475,7 +477,7 @@ def create_app(args):
                     "enable_llm_cache_for_extract": args.enable_llm_cache_for_extract,
                     "enable_llm_cache": args.enable_llm_cache,
                     "workspace": args.workspace,
-                    "max_graph_nodes": os.getenv("MAX_GRAPH_NODES"),
+                    "max_graph_nodes": args.max_graph_nodes,
                 },
                 "auth_mode": auth_mode,
                 "pipeline_busy": pipeline_status.get("busy", False),
diff --git a/lightrag/kg/mongo_impl.py b/lightrag/kg/mongo_impl.py
index ace28432..dcf99327 100644
--- a/lightrag/kg/mongo_impl.py
+++ b/lightrag/kg/mongo_impl.py
@@ -34,8 +34,6 @@ from pymongo.errors import PyMongoError  # type: ignore
 config = configparser.ConfigParser()
 config.read("config.ini", "utf-8")
 
-# Get maximum number of graph nodes from environment variable, default is 1000
-MAX_GRAPH_NODES = int(os.getenv("MAX_GRAPH_NODES", 1000))
 GRAPH_BFS_MODE = os.getenv("MONGO_GRAPH_BFS_MODE", "bidirectional")
 
 
@@ -883,7 +881,7 @@ class MongoGraphStorage(BaseGraphStorage):
         )
 
     async def get_knowledge_graph_all_by_degree(
-        self, max_depth: int = 3, max_nodes: int = MAX_GRAPH_NODES
+        self, max_depth: int, max_nodes: int
     ) -> KnowledgeGraph:
         """
         It's possible that the node with one or multiple relationships is retrieved,
@@ -961,9 +959,9 @@ class MongoGraphStorage(BaseGraphStorage):
         node_labels: list[str],
         seen_nodes: set[str],
         result: KnowledgeGraph,
-        depth: int = 0,
-        max_depth: int = 3,
-        max_nodes: int = MAX_GRAPH_NODES,
+        depth: int,
+        max_depth: int,
+        max_nodes: int,
     ) -> KnowledgeGraph:
         if depth > max_depth or len(result.nodes) > max_nodes:
             return result
@@ -1006,9 +1004,9 @@ class MongoGraphStorage(BaseGraphStorage):
     async def get_knowledge_subgraph_bidirectional_bfs(
         self,
         node_label: str,
-        depth=0,
-        max_depth: int = 3,
-        max_nodes: int = MAX_GRAPH_NODES,
+        depth: int,
+        max_depth: int,
+        max_nodes: int,
     ) -> KnowledgeGraph:
         seen_nodes = set()
         seen_edges = set()
@@ -1038,7 +1036,7 @@ class MongoGraphStorage(BaseGraphStorage):
         return result
 
     async def get_knowledge_subgraph_in_out_bound_bfs(
-        self, node_label: str, max_depth: int = 3, max_nodes: int = MAX_GRAPH_NODES
+        self, node_label: str, max_depth: int, max_nodes: int
     ) -> KnowledgeGraph:
         seen_nodes = set()
         seen_edges = set()
@@ -1152,7 +1150,7 @@ class MongoGraphStorage(BaseGraphStorage):
         self,
         node_label: str,
         max_depth: int = 3,
-        max_nodes: int = MAX_GRAPH_NODES,
+        max_nodes: int = None,
     ) -> KnowledgeGraph:
         """
         Retrieve a connected subgraph of nodes where the label includes the specified `node_label`.
@@ -1160,7 +1158,7 @@ class MongoGraphStorage(BaseGraphStorage):
         Args:
             node_label: Label of the starting node, * means all nodes
             max_depth: Maximum depth of the subgraph, Defaults to 3
-            max_nodes: Maxiumu nodes to return, Defaults to 1000
+            max_nodes: Maximum nodes to return, Defaults to global_config max_graph_nodes
 
         Returns:
             KnowledgeGraph object containing nodes and edges, with an is_truncated flag
@@ -1184,6 +1182,13 @@ class MongoGraphStorage(BaseGraphStorage):
         C → B
         C → D
         """
+        # Use global_config max_graph_nodes as default if max_nodes is None
+        if max_nodes is None:
+            max_nodes = self.global_config.get("max_graph_nodes", 1000)
+        else:
+            # Limit max_nodes to not exceed global_config max_graph_nodes
+            max_nodes = min(max_nodes, self.global_config.get("max_graph_nodes", 1000))
+
         result = KnowledgeGraph()
         start = time.perf_counter()
 
diff --git a/lightrag/kg/neo4j_impl.py b/lightrag/kg/neo4j_impl.py
index 63a3300a..b0efc4b5 100644
--- a/lightrag/kg/neo4j_impl.py
+++ b/lightrag/kg/neo4j_impl.py
@@ -36,9 +36,6 @@ from dotenv import load_dotenv
 # the OS environment variables take precedence over the .env file
 load_dotenv(dotenv_path=".env", override=False)
 
-# Get maximum number of graph nodes from environment variable, default is 1000
-MAX_GRAPH_NODES = int(os.getenv("MAX_GRAPH_NODES", 1000))
-
 config = configparser.ConfigParser()
 config.read("config.ini", "utf-8")
 
@@ -902,7 +899,7 @@ class Neo4JStorage(BaseGraphStorage):
         self,
         node_label: str,
         max_depth: int = 3,
-        max_nodes: int = MAX_GRAPH_NODES,
+        max_nodes: int = None,
     ) -> KnowledgeGraph:
         """
         Retrieve a connected subgraph of nodes where the label includes the specified `node_label`.
@@ -916,6 +913,13 @@ class Neo4JStorage(BaseGraphStorage):
             KnowledgeGraph object containing nodes and edges, with an is_truncated flag
             indicating whether the graph was truncated due to max_nodes limit
         """
+        # Get max_nodes from global_config if not provided
+        if max_nodes is None:
+            max_nodes = self.global_config.get("max_graph_nodes", 1000)
+        else:
+            # Limit max_nodes to not exceed global_config max_graph_nodes
+            max_nodes = min(max_nodes, self.global_config.get("max_graph_nodes", 1000))
+
         workspace_label = self._get_workspace_label()
         result = KnowledgeGraph()
         seen_nodes = set()
diff --git a/lightrag/kg/networkx_impl.py b/lightrag/kg/networkx_impl.py
index faff6a96..01b34566 100644
--- a/lightrag/kg/networkx_impl.py
+++ b/lightrag/kg/networkx_impl.py
@@ -26,8 +26,6 @@ from dotenv import load_dotenv
 # the OS environment variables take precedence over the .env file
 load_dotenv(dotenv_path=".env", override=False)
 
-MAX_GRAPH_NODES = int(os.getenv("MAX_GRAPH_NODES", 1000))
-
 
 @final
 @dataclass
@@ -218,7 +216,7 @@ class NetworkXStorage(BaseGraphStorage):
         self,
         node_label: str,
         max_depth: int = 3,
-        max_nodes: int = MAX_GRAPH_NODES,
+        max_nodes: int = None,
     ) -> KnowledgeGraph:
         """
         Retrieve a connected subgraph of nodes where the label includes the specified `node_label`.
@@ -232,6 +230,13 @@ class NetworkXStorage(BaseGraphStorage):
             KnowledgeGraph object containing nodes and edges, with an is_truncated flag
             indicating whether the graph was truncated due to max_nodes limit
         """
+        # Get max_nodes from global_config if not provided
+        if max_nodes is None:
+            max_nodes = self.global_config.get("max_graph_nodes", 1000)
+        else:
+            # Limit max_nodes to not exceed global_config max_graph_nodes
+            max_nodes = min(max_nodes, self.global_config.get("max_graph_nodes", 1000))
+
         graph = await self._get_graph()
 
         result = KnowledgeGraph()
diff --git a/lightrag/kg/postgres_impl.py b/lightrag/kg/postgres_impl.py
index 5750fd6e..7e696c77 100644
--- a/lightrag/kg/postgres_impl.py
+++ b/lightrag/kg/postgres_impl.py
@@ -45,9 +45,6 @@ from dotenv import load_dotenv
 # the OS environment variables take precedence over the .env file
 load_dotenv(dotenv_path=".env", override=False)
 
-# Get maximum number of graph nodes from environment variable, default is 1000
-MAX_GRAPH_NODES = int(os.getenv("MAX_GRAPH_NODES", 1000))
-
 
 class PostgreSQLDB:
     def __init__(self, config: dict[str, Any], **kwargs: Any):
@@ -2819,7 +2816,7 @@ class PGGraphStorage(BaseGraphStorage):
         self,
         node_label: str,
         max_depth: int = 3,
-        max_nodes: int = MAX_GRAPH_NODES,
+        max_nodes: int = None,
     ) -> KnowledgeGraph:
         """
         Retrieve a connected subgraph of nodes where the label includes the specified `node_label`.
@@ -2827,12 +2824,18 @@ class PGGraphStorage(BaseGraphStorage):
         Args:
             node_label: Label of the starting node, * means all nodes
             max_depth: Maximum depth of the subgraph, Defaults to 3
-            max_nodes: Maxiumu nodes to return, Defaults to 1000
+            max_nodes: Maximum nodes to return, Defaults to global_config max_graph_nodes
 
         Returns:
             KnowledgeGraph object containing nodes and edges, with an is_truncated flag
             indicating whether the graph was truncated due to max_nodes limit
         """
+        # Use global_config max_graph_nodes as default if max_nodes is None
+        if max_nodes is None:
+            max_nodes = self.global_config.get("max_graph_nodes", 1000)
+        else:
+            # Limit max_nodes to not exceed global_config max_graph_nodes
+            max_nodes = min(max_nodes, self.global_config.get("max_graph_nodes", 1000))
         kg = KnowledgeGraph()
 
         # Handle wildcard query - get all nodes
diff --git a/lightrag/lightrag.py b/lightrag/lightrag.py
index 5d96aeba..cbb5e2a8 100644
--- a/lightrag/lightrag.py
+++ b/lightrag/lightrag.py
@@ -258,6 +258,9 @@ class LightRAG:
     max_parallel_insert: int = field(default=int(os.getenv("MAX_PARALLEL_INSERT", 2)))
     """Maximum number of parallel insert operations."""
 
+    max_graph_nodes: int = field(default=get_env_value("MAX_GRAPH_NODES", 1000, int))
+    """Maximum number of graph nodes to return in knowledge graph queries."""
+
     addon_params: dict[str, Any] = field(
         default_factory=lambda: {
             "language": get_env_value("SUMMARY_LANGUAGE", "English", str)
@@ -526,18 +529,24 @@ class LightRAG:
         self,
         node_label: str,
         max_depth: int = 3,
-        max_nodes: int = 1000,
+        max_nodes: int = None,
     ) -> KnowledgeGraph:
         """Get knowledge graph for a given label
 
         Args:
             node_label (str): Label to get knowledge graph for
             max_depth (int): Maximum depth of graph
-            max_nodes (int, optional): Maximum number of nodes to return. Defaults to 1000.
+            max_nodes (int, optional): Maximum number of nodes to return. Defaults to self.max_graph_nodes.
 
         Returns:
             KnowledgeGraph: Knowledge graph containing nodes and edges
         """
+        # Use self.max_graph_nodes as default if max_nodes is None
+        if max_nodes is None:
+            max_nodes = self.max_graph_nodes
+        else:
+            # Limit max_nodes to not exceed self.max_graph_nodes
+            max_nodes = min(max_nodes, self.max_graph_nodes)
 
         return await self.chunk_entity_relation_graph.get_knowledge_graph(
             node_label, max_depth, max_nodes