diff --git a/plugins/alipay_cpn/internal/util.go b/plugins/alipay_cpn/internal/util.go
index 743f457..a59e02f 100644
--- a/plugins/alipay_cpn/internal/util.go
+++ b/plugins/alipay_cpn/internal/util.go
@@ -24,6 +24,9 @@ func req(config *Config, req *po.Param) (url.Values, error) {
 		if kv.Key == "sign" {
 			continue
 		}
+		if kv.Value == "" {
+			continue
+		}
 		uv.Set(kv.Key, kv.Value)
 		strToBeSigned.WriteString(fmt.Sprintf("%s=%s&", kv.Key, kv.Value))
 	}
@@ -68,6 +71,9 @@ func Verify(n *po.Notify, publicKeyPEM string) (bool, error) {
 		if kv.Key == "sign_type" {
 			continue
 		}
+		if kv.Value == "" {
+			continue
+		}
 		uv.Set(kv.Key, kv.Value)
 		strToBeSigned.WriteString(fmt.Sprintf("%s=%s&", kv.Key, kv.Value))
 	}