diff --git a/encoding/gjson/gjson_z_unit_test.go b/encoding/gjson/gjson_z_unit_test.go
index 5ab828a8c0e..55faf5d0490 100644
--- a/encoding/gjson/gjson_z_unit_test.go
+++ b/encoding/gjson/gjson_z_unit_test.go
@@ -14,6 +14,7 @@ import (
 	"github.com/gogf/gf/v2/container/gvar"
 	"github.com/gogf/gf/v2/encoding/gjson"
 	"github.com/gogf/gf/v2/frame/g"
+	"github.com/gogf/gf/v2/os/gtime"
 	"github.com/gogf/gf/v2/test/gtest"
 	"github.com/gogf/gf/v2/util/gconv"
 )
@@ -587,3 +588,15 @@ func Test_Issue1747(t *testing.T) {
 		t.Assert(j.Get("2"), `336371793314971759`)
 	})
 }
+
+// https://github.com/gogf/gf/issues/2520
+func Test_Issue2520(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		type test struct {
+			Unique *gvar.Var `json:"unique"`
+		}
+
+		t2 := test{Unique: gvar.New(gtime.Date())}
+		t.Assert(gjson.MustEncodeString(t2), gjson.New(t2).MustToJsonString())
+	})
+}
diff --git a/util/gconv/gconv_map.go b/util/gconv/gconv_map.go
index 9e3605cb58f..f9a510eeca3 100644
--- a/util/gconv/gconv_map.go
+++ b/util/gconv/gconv_map.go
@@ -306,7 +306,9 @@ func doMapConvertForMapOrStructValue(in doMapConvertForMapOrStructValueInput) in
 					dataMap[mapK] = mapV
 				}
 			}
-			return dataMap
+			if len(dataMap) > 0 {
+				return dataMap
+			}
 		}
 		// Using reflect for converting.
 		var (