diff --git a/.env.example b/.env.example
index b652847b..82b9ca70 100644
--- a/.env.example
+++ b/.env.example
@@ -44,6 +44,8 @@ MAX_TOKENS=32768
 EMBEDDING_DIM=1024
 MAX_EMBED_TOKENS=8192
 #HISTORY_TURNS=3
+#CHUNK_SIZE=1200
+#CHUNK_OVERLAP_SIZE=100
 
 # Security (empty for no key)
 LIGHTRAG_API_KEY=your-secure-api-key-here
diff --git a/lightrag/api/lightrag_server.py b/lightrag/api/lightrag_server.py
index e000dc0e..da15d212 100644
--- a/lightrag/api/lightrag_server.py
+++ b/lightrag/api/lightrag_server.py
@@ -383,14 +383,14 @@ def parse_args() -> argparse.Namespace:
 
     parser.add_argument(
         "--chunk_size",
-        default=1200,
-        help="chunk token size default 1200",
+        default=get_env_value("CHUNK_SIZE", 1200),
+        help="chunk chunk size default 1200",
     )
 
     parser.add_argument(
         "--chunk_overlap_size",
-        default=100,
-        help="chunk token size default 1200",
+        default=get_env_value("CHUNK_OVERLAP_SIZE", 100),
+        help="chunk overlap size default 100",
     )
 
     def timeout_type(value):