In view of the incomplete understanding on the karst origin and distribution characteristics of paleo-landform of the Middle Permian Qixia Formation in the Sichuan Basin, we studied geological responses of its karst reservoirs thoroughly. The research indi- cated that Qixia interlayer karsts were formed due to the exposure and erosion of third-grade sequence boundaries and the transient exposure of high-frequency sequence interfaces of the highstand systems tract. Based on the isopach map, paleogeographic environ- ment and hydrodynamic forces of the Qixia Formation, its top paleo-landform was divided into three second grade geomorphic units, i.e. the middle ramp facies belt in western Sichuan, the inne~platform shoal facies belt in northeastern Sichuan and the Luzhou pa- leo-uplift in southern Sichuan. The sedimentary microtopographic high formed both in bioclastic beaches of the middle ramp of west- ern $ichuan and in inner-platform shoals of northeastern Sichuan, along with the paleo-uplift and its slopes of southern Sichuan, is favorable for the development of karst reservoirs in the Qixia Formation. On the basis of this new understanding and characteristics of the hydrocarbon generating intensity of source rocks, four favorable zones were proposed for the exploration of karst reservoirs in the Oixia Formation.