那你这样定义吧 public class Province { public string ProvinceCode{get;set;} public List<City> Citys{get;set;} public void AddCity(City city) { if(Citys==null) Citys=new List<City>(); Citys.Add(city); } } public class City { public string CityCode{get;set;} public List<County> Countys{get;set;} public void AddCounty(County county) { if(Countys==null) Countys=new List<County>(); Countys.Add(county); } } public class County { public string CountyCode{get;set;} }