diff --git a/README.md b/README.md
index a8f8aa0..80118c8 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ A global proxy for go modules. see: [https://goproxy.io](https://goproxy.io)
 
 ## Started
     
-    ./goproxy -listen=0.0.0.0:80 -root=/ext
+    ./goproxy -listen=0.0.0.0:80 -cacheDir=/cache
 
 ## Docker
 
@@ -17,11 +17,12 @@ A global proxy for go modules. see: [https://goproxy.io](https://goproxy.io)
 
 Use the -v flag to persisting the proxy module data (change ___go_repo___ to your own dir):
 
-    docker run --name goproxy -d -p80:8081 -v go_repo:/ext goproxyio/goproxy
+    docker run --name goproxy -d -p80:8081 -v go_repo:/cache goproxyio/goproxy
 
 ## Docker Compose
 
     docker-compose up
 
 ## Appendix
-1. set `$GOPROXY` to chain your proxy or disable the proxy
+
+1. set `$GOPROXY` to change your proxy or disable the proxy
diff --git a/main.go b/main.go
index d6e4ebe..82acc18 100644
--- a/main.go
+++ b/main.go
@@ -4,43 +4,45 @@ package main
 
 import (
 	"flag"
-	"github.com/goproxyio/goproxy/pkg/proxy"
 	"log"
 	"net/http"
 	"os"
 	"path/filepath"
 	"time"
+
+	"github.com/goproxyio/goproxy/pkg/proxy"
 )
 
 var listen string
-var root string
+var cacheDir string
 
 func init() {
 	log.SetOutput(os.Stdout)
-	flag.StringVar(&root, "root", "/go", "root cache dir to save")
+	flag.StringVar(&cacheDir, "cacheDir", "", "go modules cache dir")
 	flag.StringVar(&listen, "listen", "0.0.0.0:8081", "service listen address")
 	flag.Parse()
-	if err := os.MkdirAll(root, os.ModePerm); err != nil {
-		log.Fatalf("goproxy: make root dir failed: %s", err)
-	}
 }
 
 func main() {
-
-	// sigs := make(chan os.Signal)
-	// signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
-
 	log.Printf("goproxy: %s inited. listen on %s\n", time.Now().Format("2006-01-02 15:04:05"), listen)
 
-	cacheDir := filepath.Join(root, "pkg", "mod", "cache", "download")
-	if _, err := os.Stat(cacheDir); os.IsNotExist(err) {
-		log.Printf("goproxy: cache dir %s is not exist. To create\n", cacheDir)
-		if err := os.MkdirAll(cacheDir, 0755); err != nil {
+	if cacheDir == "" {
+		cacheDir = "/go"
+		gpEnv := os.Getenv("GOPATH")
+		gp := filepath.SplitList(gpEnv)
+		if gp[0] != "" {
+			cacheDir = gp[0]
+		}
+	}
+	fullCacheDir := filepath.Join(cacheDir, "pkg", "mod", "cache", "download")
+	if _, err := os.Stat(fullCacheDir); os.IsNotExist(err) {
+		log.Printf("goproxy: cache dir %s is not exist. To create it.\n", fullCacheDir)
+		if err := os.MkdirAll(fullCacheDir, 0755); err != nil {
 			log.Fatalf("make cache dir failed: %s", err)
 		}
 	}
 
-	http.Handle("/", proxy.NewProxy(root))
+	http.Handle("/", proxy.NewProxy(cacheDir))
 	// TODO: TLS, graceful shutdown
 	err := http.ListenAndServe(listen, nil)
 	if nil != err {
diff --git a/pkg/proxy/proxy.go b/pkg/proxy/proxy.go
index 78a6ec3..7530b9b 100644
--- a/pkg/proxy/proxy.go
+++ b/pkg/proxy/proxy.go
@@ -18,10 +18,10 @@ var cacheDir string
 var innerHandle http.Handler
 
 func NewProxy(cache string) http.Handler {
-	modfetch.PkgMod = filepath.Join(cache, "pkg/mod")
-	codehost.WorkRoot = filepath.Join(modfetch.PkgMod, "cache/vcs")
+	modfetch.PkgMod = filepath.Join(cache, "pkg", "mod")
+	codehost.WorkRoot = filepath.Join(modfetch.PkgMod, "cache", "vcs")
 
-	cacheDir = filepath.Join(modfetch.PkgMod, "cache/download")
+	cacheDir = filepath.Join(modfetch.PkgMod, "cache", "download")
 	innerHandle = http.FileServer(http.Dir(cacheDir))
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -71,10 +71,12 @@ func NewProxy(cache string) http.Handler {
 				rev, err := repo.Stat("latest")
 				if err != nil {
 					errLogger.Printf("latest failed: %v", err)
+					return
 				}
 				if err := downloadMod(modPath, rev.Version); err != nil {
 					errLogger.Printf("download get err %s", err)
 				}
+
 			}
 
 			if strings.HasSuffix(r.URL.Path, "/@v/list") {