diff --git a/README.md b/README.md
index e8db9a7..42e4709 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ a golang performence testing platform
 
 ## demo client
 ```go
-	perfm := perfm.New(perfm.NewConfig())
+	perfm := perfm.New(perfm.WithParallel(5))
 	perfm.Registe(func() error {
 		_, err := http.Get("http://www.baidu.com")
 		return err
diff --git a/config.go b/config.go
index 2480262..2050851 100644
--- a/config.go
+++ b/config.go
@@ -16,7 +16,7 @@ type Config struct {
 }
 
 //NewConfig gen the config
-func NewConfig(options ...Options) Config {
+func newConfig(options ...Options) Config {
 	c := Config{10, 4, 0, false, 1, 6553500, 15, 1.4, 1000000, 1000}
 	for _, o := range options {
 		o(&c)
diff --git a/demo/main.go b/demo/main.go
index 8fa7676..e4e0bf5 100644
--- a/demo/main.go
+++ b/demo/main.go
@@ -7,10 +7,8 @@ import (
 )
 
 func main() {
-	conf := perfm.NewConfig(perfm.WithBinsNumber(15), perfm.WithMinValue(0),
-		perfm.WithGrowthFactor(0.4), perfm.WithBaseBucketSize(20), perfm.WithParallel(5))
 
-	perfm := perfm.New(conf)
+	perfm := perfm.New(perfm.WithBinsNumber(15), perfm.WithMinValue(0), perfm.WithGrowthFactor(0.4), perfm.WithBaseBucketSize(20), perfm.WithParallel(5))
 
 	perfm.Registe(func() error {
 		_, err := http.Get("http://www.baidu.com")
diff --git a/perfm.go b/perfm.go
index 1796060..7d69b7e 100644
--- a/perfm.go
+++ b/perfm.go
@@ -41,7 +41,9 @@ type perfmonitor struct {
 }
 
 //New gengrate the perfm monitor
-func New(conf Config) PerfMonitor {
+func New(options ...Options) PerfMonitor {
+	conf := newConfig(options...)
+
 	histopt := hist.HistogramOptions{
 		NumBuckets:     conf.BinsNumber,
 		GrowthFactor:   conf.GrowthFactor,