In ancient China,there emerged many important cities in southern Hebei province in different periods such as Handan,Yecheng and Darning.Most of them later developed into key cities in southern Hebei province and even of the northern part of China.Two changes of key city in southern Hebei province respectively occurred in late Eastern Hart Dynasty and late Northern Zhou Dynasty.The first one is from Handan to Yecheng,and the second one is from Yecheng to Darning.this social phenomenon resulted from the macro historical environment of that period,the special geographical conditions of southern Hebei province and the development of water and land transportation.