diff --git a/README.md b/README.md
index 91b9859..4482c14 100644
--- a/README.md
+++ b/README.md
@@ -59,9 +59,9 @@
 
 ## `GET /line`
 
-| Query  | Required | Type    | Default |
-| :----- | :------- | :------ | :------ |
-| `fill` |          | boolean | `false` |
+| Query  | Required | Type   | Default | Description        |
+| :----- | :------- | :----- | :------ | :----------------- |
+| `line` |          | string | `fill`  | `fill` or `nofill` |
 
 
 | `data`  | Required | Type     |
diff --git a/go.mod b/go.mod
index 7ab8394..84726e6 100644
--- a/go.mod
+++ b/go.mod
@@ -10,7 +10,7 @@ require (
 	github.com/mcuadros/go-defaults v1.2.0
 	github.com/sirupsen/logrus v1.9.3
 	github.com/stretchr/testify v1.8.4
-	github.com/vicanso/go-charts/v2 v2.6.1
+	github.com/vicanso/go-charts/v2 v2.6.3
 	github.com/wcharczuk/go-chart/v2 v2.1.1
 )
 
diff --git a/go.sum b/go.sum
index 7d82eb5..7bd09a9 100644
--- a/go.sum
+++ b/go.sum
@@ -97,8 +97,8 @@ github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyC
 github.com/valyala/fasttemplate v1.2.1/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=
 github.com/valyala/fasttemplate v1.2.2 h1:lxLXG0uE3Qnshl9QyaK6XJxMXlQZELvChBOCmQD0Loo=
 github.com/valyala/fasttemplate v1.2.2/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=
-github.com/vicanso/go-charts/v2 v2.6.1 h1:xWODVa4KtzkZrbUNd6WQunqGyFWXgaUeeXMQkFm9RuE=
-github.com/vicanso/go-charts/v2 v2.6.1/go.mod h1:Ii2KDI3udTG1wPtiTnntzjlUBJVJTqNscMzh3oYHzUk=
+github.com/vicanso/go-charts/v2 v2.6.3 h1:AP+zVZw27nt7kjxY5js70M3YfroDRCodrpdqW/Gdxh4=
+github.com/vicanso/go-charts/v2 v2.6.3/go.mod h1:Ii2KDI3udTG1wPtiTnntzjlUBJVJTqNscMzh3oYHzUk=
 github.com/wcharczuk/go-chart/v2 v2.1.1 h1:2u7na789qiD5WzccZsFz4MJWOJP72G+2kUuJoSNqWnE=
 github.com/wcharczuk/go-chart/v2 v2.1.1/go.mod h1:CyCAUt2oqvfhCl6Q5ZvAZwItgpQKZOkCJGb+VGv6l14=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
diff --git a/pkg/chart.go b/pkg/chart.go
index 0afc3fc..dc4be78 100644
--- a/pkg/chart.go
+++ b/pkg/chart.go
@@ -48,7 +48,7 @@ type ChartRequest struct {
 	Width         int    `json:"width" query:"width" form:"width" default:"1024"`
 	Height        int    `json:"height" query:"height" form:"height" default:"768"`
 	Style         string `json:"style" query:"style" form:"style" default:"vertical"`
-	Fill          bool   `json:"fill" query:"fill" form:"fill" default:"false"`
+	Line          string `json:"line" query:"line" default:"nofill" validate:"oneof=nofill fill" message:"line must be fill"`
 	Output        string `json:"output" query:"output" form:"output" default:"png"`
 }
 
diff --git a/pkg/line_chart.go b/pkg/line_chart.go
index 268b75a..a190290 100644
--- a/pkg/line_chart.go
+++ b/pkg/line_chart.go
@@ -17,6 +17,10 @@ func NewLineChart() *LineChart {
 }
 
 func (c *LineChart) Get(xData []string, yData [][]float64, names []string, req *ChartRequest) ([]byte, error) {
+	fill := false
+	if req.Line == "fill" {
+		fill = true
+	}
 	p, err := charts.LineRender(
 		yData,
 		charts.HeightOptionFunc(req.Height),
@@ -44,7 +48,7 @@ func (c *LineChart) Get(xData []string, yData [][]float64, names []string, req *
 			opt.ValueFormatter = func(f float64) string {
 				return fmt.Sprintf("%s %s", NumberToK(&f), req.Metric)
 			}
-			opt.FillArea = req.Fill
+			opt.FillArea = fill
 
 			idx := len(opt.SeriesList) - 1
 			if len(opt.SeriesList) > 1 {