diff --git a/Makefile b/Makefile
index c76821e..1a157af 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,7 @@
 .PHONY: all prepare force-build build push
 
+IMAGE_NAME:=focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest-slim
+
 all: build
 
 prepare:
@@ -8,10 +10,10 @@ prepare:
 	cp JOJ3/build/joj3 JOJ3/build/repo-health-checker bin/
 
 force-build: prepare
-	docker build --no-cache -t focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest-slim .
+	docker build --no-cache -t $(IMAGE_NAME) .
 
 build: prepare
-	docker build -t focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest-slim .
+	docker build -t $(IMAGE_NAME) .
 
 push:
-	docker push focs.ji.sjtu.edu.cn:5000/gitea/runner-images:focs-ubuntu-latest-slim
+	docker push $(IMAGE_NAME)