After integration analysis of outcrop, core, logging and seismic data, it is recognized that Upper PermianChangxing Formation is carbonate platform deposition in Dianjiang-Wanxian area, Sichuan Basin. Because of E-mei taphrogeny, two platforms and two trenches developed in Dianjiang-Wanxian area. Based on the establishment of third-order sequence framework, the distribution of sedimentary facies is studied. It is considered that there is a carbonate platform system during the Changxing period in Dianjiang-Wanxian area, which is controlled by Kaijiang-Liangping trench and includes open platform, platform edge and ramp facies. Reef, bioclastic shoal and tidal flat facies developed in the platform edge during the high system tract period of the two third-order sequences of Changxing Formation are favorable facies belts. And only a little reef and shoal developed in platform edge during the transgression systemtract period of the upper third-order sequence. Being affected by regression, reef and shoal moved to the east-north of the study area.