Abstract: Based on analyzing the formation conditions of gas reservoirs of K₁sh+yc~K₁d₂ accumulation system in XuJiaWeiZi area, this paper points out that this accumulation system owns the characteristics of high temperature, high pressure and high salinity. The main controlling factors of the formation of gas reservoir are analyzed, which are the matching relation between gas sourcerock and caprock, distribution of caprock, surface of unconformity and ancient uplift. The matching relation between gas sourcerock and caprock controls the gas distribution and accumulation amount. The distribution of caprock controls the place of gas accumulation. Surface of unconformity controls the gas migration and accumulation. Ancient uplift controls the gas accumulation.