diff --git a/proxy/connection.go b/proxy/connection.go
index cb99e9d..f97a081 100644
--- a/proxy/connection.go
+++ b/proxy/connection.go
@@ -105,10 +105,17 @@ func (connCtx *ConnContext) initHttpServerConn() {
 		return
 	}
 
+	var useProxy func(*http.Request) (*url.URL, error)
+	if len(connCtx.proxy.Opts.Upstream) > 0 {
+		upstreamUrl, _ := url.Parse(connCtx.proxy.Opts.Upstream)
+		useProxy = http.ProxyURL(upstreamUrl)
+	} else {
+		useProxy = http.ProxyFromEnvironment
+	}
 	serverConn := newServerConn()
 	serverConn.client = &http.Client{
 		Transport: &http.Transport{
-			Proxy: http.ProxyFromEnvironment,
+			Proxy: useProxy,
 			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
 				c, err := (&net.Dialer{}).DialContext(ctx, network, addr)
 				if err != nil {
diff --git a/proxy/proxy.go b/proxy/proxy.go
index 956653f..1bf8f20 100644
--- a/proxy/proxy.go
+++ b/proxy/proxy.go
@@ -16,6 +16,7 @@ type Options struct {
 	StreamLargeBodies int64 // 当请求或响应体大于此字节时，转为 stream 模式
 	SslInsecure       bool
 	CaRootPath        string
+	Upstream          string
 }
 
 type Proxy struct {