diff --git a/README.md b/README.md
index 32bca22..58c0d1e 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,8 @@ Usage of go-mitmproxy:
     	show version
   -web_addr string
     	web interface listen addr (default ":9081")
+  -cert_path string
+    	path of generate cert files
 ```
 
 ## Usage as package
diff --git a/README_CN.md b/README_CN.md
index c6fa7ea..a0787f9 100644
--- a/README_CN.md
+++ b/README_CN.md
@@ -54,6 +54,8 @@ Usage of go-mitmproxy:
     	show version
   -web_addr string
     	web interface listen addr (default ":9081")
+  -cert_path string
+    	path of generate cert files
 ```
 
 ## 作为包引入
diff --git a/cert/cert.go b/cert/cert.go
index 6934008..0d0f704 100644
--- a/cert/cert.go
+++ b/cert/cert.go
@@ -67,10 +67,23 @@ func NewCA(path string) (*CA, error) {
 		return nil, err
 	}
 	log.Debug("create root ca")
-
 	return ca, nil
 }
 
+func CopyFile(dstName, srcName string) (written int64, err error) {
+	src, err := os.Open(srcName)
+	if err != nil {
+		return
+	}
+	defer src.Close()
+	dst, err := os.OpenFile(dstName, os.O_WRONLY|os.O_CREATE, 0644)
+	if err != nil {
+		return
+	}
+	defer dst.Close()
+	return io.Copy(dst, src)
+}
+
 func getStorePath(path string) (string, error) {
 	if path == "" {
 		homeDir, err := os.UserHomeDir()
@@ -117,6 +130,10 @@ func (ca *CA) caCertFile() string {
 	return filepath.Join(ca.StorePath, "mitmproxy-ca-cert.pem")
 }
 
+func (ca *CA) caCertCerFile() string {
+	return filepath.Join(ca.StorePath, "mitmproxy-ca-cert.cer")
+}
+
 func (ca *CA) load() error {
 	caFile := ca.caFile()
 	stat, err := os.Stat(caFile)
@@ -234,7 +251,6 @@ func (ca *CA) save() error {
 		return err
 	}
 	defer file.Close()
-
 	return ca.saveTo(file)
 }
 
@@ -244,8 +260,17 @@ func (ca *CA) saveCert() error {
 		return err
 	}
 	defer file.Close()
+	err = ca.saveCertTo(file)
+
+	cerFile, err := os.Create(ca.caCertCerFile())
+	if err != nil {
+		return err
+	}
+	defer cerFile.Close()
+
+	CopyFile(cerFile.Name(), file.Name())
 
-	return ca.saveCertTo(file)
+	return err
 }
 
 func (ca *CA) GetCert(commonName string) (*tls.Certificate, error) {
diff --git a/cmd/go-mitmproxy/main.go b/cmd/go-mitmproxy/main.go
index 7dfdd6a..5b5b127 100644
--- a/cmd/go-mitmproxy/main.go
+++ b/cmd/go-mitmproxy/main.go
@@ -16,7 +16,8 @@ import (
 )
 
 type Config struct {
-	version bool
+	version  bool
+	certPath string
 
 	addr         string
 	webAddr      string
@@ -38,6 +39,7 @@ func loadConfig() *Config {
 	flag.StringVar(&config.dump, "dump", "", "dump filename")
 	flag.IntVar(&config.dumpLevel, "dump_level", 0, "dump level: 0 - header, 1 - header + body")
 	flag.StringVar(&config.mapperDir, "mapper_dir", "", "mapper files dirpath")
+	flag.StringVar(&config.certPath, "cert_path", "", "path of generate cert files")
 	flag.Parse()
 
 	return config
@@ -63,7 +65,7 @@ func main() {
 		SslInsecure:       config.ssl_insecure,
 	}
 
-	p, err := proxy.NewProxy(opts)
+	p, err := proxy.NewProxy(opts,config.certPath)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/proxy/middle.go b/proxy/middle.go
index 620c450..392b47e 100644
--- a/proxy/middle.go
+++ b/proxy/middle.go
@@ -73,8 +73,8 @@ type Middle struct {
 	Server   *http.Server
 }
 
-func NewMiddle(proxy *Proxy) (Interceptor, error) {
-	ca, err := cert.NewCA("")
+func NewMiddle(proxy *Proxy,path string) (Interceptor, error) {
+	ca, err := cert.NewCA(path)
 	if err != nil {
 		return nil, err
 	}
diff --git a/proxy/proxy.go b/proxy/proxy.go
index 5d66941..abb4183 100644
--- a/proxy/proxy.go
+++ b/proxy/proxy.go
@@ -30,7 +30,7 @@ type Proxy struct {
 	Addons            []addon.Addon
 }
 
-func NewProxy(opts *Options) (*Proxy, error) {
+func NewProxy(opts *Options,path string) (*Proxy, error) {
 	proxy := new(Proxy)
 	proxy.Version = "0.1.5"
 
@@ -65,7 +65,7 @@ func NewProxy(opts *Options) (*Proxy, error) {
 		},
 	}
 
-	interceptor, err := NewMiddle(proxy)
+	interceptor, err := NewMiddle(proxy,path)
 	if err != nil {
 		return nil, err
 	}