diff --git a/casdoorsdk/product.go b/casdoorsdk/product.go
index 891f210..920e751 100644
--- a/casdoorsdk/product.go
+++ b/casdoorsdk/product.go
@@ -124,23 +124,28 @@ func (c *Client) DeleteProduct(product *Product) (bool, error) {
 	return affected, err
 }
 
-func (c *Client) BuyProduct(name string, providerName string) (*Product, error) {
+func (c *Client) BuyProduct(name string, providerName string, userName string) (*Product, error) {
 	queryMap := map[string]string{
 		"id":           fmt.Sprintf("%s/%s", c.OrganizationName, name),
 		"providerName": providerName,
+		"userName":     userName,
 	}
 
-	url := c.GetUrl("buy-product", queryMap)
+	resp, err := c.DoPost("buy-product", queryMap, []byte(""), false, false)
+	if err != nil {
+		return nil, err
+	}
 
-	bytes, err := c.DoGetBytes(url)
+	productJson, err := json.Marshal(resp.Data)
 	if err != nil {
 		return nil, err
 	}
 
-	var product *Product
-	err = json.Unmarshal(bytes, &product)
+	var product Product
+	err = json.Unmarshal(productJson, &product)
 	if err != nil {
 		return nil, err
 	}
-	return product, nil
+
+	return &product, nil
 }
diff --git a/casdoorsdk/product_global.go b/casdoorsdk/product_global.go
index 3147de4..e6426b2 100644
--- a/casdoorsdk/product_global.go
+++ b/casdoorsdk/product_global.go
@@ -38,6 +38,6 @@ func DeleteProduct(product *Product) (bool, error) {
 	return globalClient.DeleteProduct(product)
 }
 
-func BuyProduct(name string, providerName string) (*Product, error) {
-	return globalClient.BuyProduct(name, providerName)
+func BuyProduct(name string, providerName string, userName string) (*Product, error) {
+	return globalClient.BuyProduct(name, providerName, userName)
 }
diff --git a/casdoorsdk/product_test.go b/casdoorsdk/product_test.go
index a30246d..a9ebfa1 100644
--- a/casdoorsdk/product_test.go
+++ b/casdoorsdk/product_test.go
@@ -34,9 +34,10 @@ func TestProduct(t *testing.T) {
 		Description: "Casdoor Website",
 		Tag:         "auto_created_product_for_plan",
 
-		Quantity: 999,
-		Sold:     0,
-		State:    "Published",
+		Quantity:  999,
+		Sold:      0,
+		State:     "Published",
+		Providers: []string{"provider_payment_dummy"},
 	}
 	_, err := AddProduct(product)
 	if err != nil {
@@ -85,6 +86,14 @@ func TestProduct(t *testing.T) {
 		t.Fatalf("Failed to update object, description mismatch: %s != %s", updatedProduct.Description, updatedDescription)
 	}
 
+	boughtProduct, err := BuyProduct(name, "provider_payment_dummy", "admin")
+	if err != nil {
+		t.Fatalf("Failed to buy product: %v", err)
+	}
+	if boughtProduct == nil {
+		t.Fatalf("Failed to buy product: nil response")
+	}
+
 	// Delete the object
 	_, err = DeleteProduct(product)
 	if err != nil {