Dictionary<string, object> dic = new Dictionary<string, object>(); dic.Add("DistrictID_1", "123"); dic.Add("Dist_1", "456"); dic.Add("DistD_1", "555"); dic.Add("Dff_1", "666"); dic.Add("DistrictID_2", "123"); dic.Add("Dist_2", "456"); dic.Add("DistD_2", "555"); dic.Add("Dff_2", "666"); var re = dic.Where(p => p.Key == "DistrictID_1").Select(p => p.Key); var formList = (from p in dic where p.Key.Contains("_1") select p); Dictionary<string, object> dic1 = formList.ToDictionary(k => k.Key, v => v.Val