diff --git a/deploy/.env.example b/deploy/.env.example
index ffea8be4..60ec51ec 100644
--- a/deploy/.env.example
+++ b/deploy/.env.example
@@ -58,6 +58,14 @@ ADMIN_PASSWORD=
 JWT_SECRET=
 JWT_EXPIRE_HOUR=24
 
+# -----------------------------------------------------------------------------
+# Configuration File (Optional)
+# -----------------------------------------------------------------------------
+# Path to custom config file (relative to docker-compose.yml directory)
+# Copy config.example.yaml to config.yaml and modify as needed
+# Leave unset to use default ./config.yaml
+#CONFIG_FILE=./config.yaml
+
 # -----------------------------------------------------------------------------
 # Gemini OAuth (OPTIONAL, required only for Gemini OAuth accounts)
 # -----------------------------------------------------------------------------
diff --git a/deploy/docker-compose.yml b/deploy/docker-compose.yml
index 17e75e2a..bece2f95 100644
--- a/deploy/docker-compose.yml
+++ b/deploy/docker-compose.yml
@@ -29,7 +29,9 @@ services:
       # Data persistence (config.yaml will be auto-generated here)
       - sub2api_data:/app/data
       # Mount custom config.yaml (optional, overrides auto-generated config)
-      - ./config.yaml:/app/data/config.yaml:ro
+      # Set CONFIG_FILE in .env to specify a custom config file path
+      # Default: ./config.yaml (copy from config.example.yaml and modify)
+      - ${CONFIG_FILE:-./config.yaml}:/app/data/config.yaml:ro
     environment:
       # =======================================================================
       # Auto Setup (REQUIRED for Docker deployment)