Abstract: The indicators of Yanchang-7 formation in Jiyuan region,such as total organic carbon,total hydrocarbon content and pyrolysis hydrocarbons yield reach the criteria of good source rock,with a strong hydrocarbon generation capacity.There are four main control factors in Jiyuan region.High quality source rocks provide the material basis for reservoir formation,while the underwater distributary channel sand bodies and dissolution pore provide the space.Moreover,the residual pressure provides the main impetus for the hydrocarbon migration,and oil and gas move along sands and cracks,developing the multi-layer reservoirs.The main control factors have a different effect on the different layer reservoirs.From Chang 2 group to Chang 9 group,sedimentation and diagenesis have a gradually increasing control,while tectonism has a gradual weakened control.There are mainly two kinds of accumulation models in the study area.