Abstract: Baidong area is located in Binhai region in Qikou sag,prolific oil gas depression,a east- west large anticline structure formded by two phase structure superposition.In the beginning of exploration,the target layer is Palaeogene Dongying formation and Neocene,the middle graben structure is main target,though it shows oil and gas but no breakthrough.Fine Study shows that Shahejie reservoir is a large anticline attached to Haihe fault,which is located in the main part of Qikou sag,rich in gas resource.The difference of structural regionalization,the distance of provenance and the relationship between reservoir and seal combination configuration determined main body in eastern Baidong region developed bottom Es1 tectonic reservoir,west slope formed tectonic lithologic gas reservoir,including Dongying formations,middle Es1,bottom Es1 formations.The paper provides guiding significance for the future oil and gas exploration in the different structure part.