Abstract: Faults are well developed in Liuzan region in Jidong (eastern Hebei) oil field,and there are more than thirty faults in 40km².But there are several key issues that need to be solved,such as when these faults wre formed,what function these faults acted on oil and gas accumulation and pool formation,and does hydrocarbon accumulation results in faulting or vice rersa? These are critical problems in pool formation study,as well as in resources assessment in this region and identification of favorable exploration targets.The author's study shows there is a sequence for fault formation.Fault formation and distribution are controlled by boundary fault of Baigezhuang,Shuohe and Gaoliu.Fault played different roles in pool formations in different times.