Abstract: This paper studies the pre?Jurassic paleogeomorphology, Fuxian-Yan’an Y8 sedimentary facies, the top layer structure and the hydrocarbon accumulation pattern in order to make clear the distribution of Jurassic reservoir and the main controlling factors of the Middle and Lower Jurassic different horizons reservoirs. And the original paleogeomorphology features of "three slopes, three highlands, four valleys and ten interchannel hills" in Longdong area are restored. The results show that the Fuxian and Y10 reservoirs are mainly distributed in the slope and the interchannel hill areas. Y9 and Y8 reservoirs are located in the areas with distributary channel microfacies of delta plain matched with the nose?like uplift. The summarized four hydrocarbon accumulation patterns of the Jurassic are slope pattern, interchannel hill pattern, paleo?valley pattern and highland pattern. It is suggested that Fuxian and Y10 reservoirs are mainly controlled by pal?aeogeomorphology; Y9 and Y8 reservoirs are controlled by sedimentary facies and nose?like structure, and the palaeogeomorphology controls on hydrocarbon accumulation show down from Fuxian reservoir to Y10, Y9, Y8 reservoirs of Yan’an formation