The Longtan Formation shale developed in the upper two Permian of Sichuan basin is widely distributed, and has potential to become the next main gas producing horizon of shale gas. On the basis of summarizing the research status of Longtan Formation in the east of Sichuan Province in recent years, through field profile research, logging data interpretation and indoor microscopic thin slices, combined with the development characteristics of mud shale in the Longtan Formation in the study area, the influence of the sediment shale thickness characteristics and shale combination characteristics is studied. The results show that the shale assemblage and thickness are controlled by sedimentary environments in southeastern Sichuan. The main shale assemblage of littoral facies is mud-encased sand, the thickest. The main shale assemblage of tidal flat facies is mud pack sand, and the effective thickness is only inferior to the shore facies. The shale assemblage of mixed continental shelf facies is mainly covered by mud and ash. There is no shale assemblage in the basin facies. It has a certain significance to further discuss the influence of sedimentary environment on the development characteristics of shale.