diff --git a/rpc/args.go b/rpc/args.go
index 96188d02e..921d8e98c 100644
--- a/rpc/args.go
+++ b/rpc/args.go
@@ -664,9 +664,8 @@ type FilterIdArgs struct {
 }
 
 func (args *FilterIdArgs) UnmarshalJSON(b []byte) (err error) {
-	var obj []string
-	r := bytes.NewReader(b)
-	if err := json.NewDecoder(r).Decode(&obj); err != nil {
+	var obj []interface{}
+	if err := json.Unmarshal(b, &obj); err != nil {
 		return NewDecodeParamError(err.Error())
 	}
 
@@ -674,7 +673,11 @@ func (args *FilterIdArgs) UnmarshalJSON(b []byte) (err error) {
 		return NewInsufficientParamsError(len(obj), 1)
 	}
 
-	args.Id = int(common.Big(obj[0]).Int64())
+	var num int64
+	if err := numString(obj[0], &num); err != nil {
+		return err
+	}
+	args.Id = int(num)
 
 	return nil
 }
diff --git a/rpc/args_test.go b/rpc/args_test.go
index 9325b1c9b..7bbf729f2 100644
--- a/rpc/args_test.go
+++ b/rpc/args_test.go
@@ -1056,6 +1056,36 @@ func TestFilterIdArgs(t *testing.T) {
 	}
 }
 
+func TestFilterIdArgsInvalid(t *testing.T) {
+	input := `{}`
+
+	args := new(FilterIdArgs)
+	str := ExpectDecodeParamError(json.Unmarshal([]byte(input), &args))
+	if len(str) > 0 {
+		t.Errorf(str)
+	}
+}
+
+func TestFilterIdArgsEmpty(t *testing.T) {
+	input := `[]`
+
+	args := new(FilterIdArgs)
+	str := ExpectInsufficientParamsError(json.Unmarshal([]byte(input), &args))
+	if len(str) > 0 {
+		t.Errorf(str)
+	}
+}
+
+func TestFilterIdArgsBool(t *testing.T) {
+	input := `[true]`
+
+	args := new(FilterIdArgs)
+	str := ExpectInvalidTypeError(json.Unmarshal([]byte(input), &args))
+	if len(str) > 0 {
+		t.Errorf(str)
+	}
+}
+
 func TestWhsiperFilterArgs(t *testing.T) {
 	input := `[{"topics": ["0x68656c6c6f20776f726c64"], "to": "0x34ag445g3455b34"}]`
 	expected := new(WhisperFilterArgs)