Based on comprehensive analysis, the frame of sequence stratigraphy is confirmed. The Changxing Formation can be divided into two sequences and the Feixianguan Formation into two sequences. Under the control of sequence framework, the lithofacies palaeogeography is mapped and the evolution is analyzed. It is considered that different platform margins develop in different areas around Kaijiang-Liangping Trough. According to the logging data and seismic data, three models of platform margin are set up: (1) the "progradating platform margin" represented by the one in Jiange area, which is characterized by reef and oolite shoal progradation to the trough center but thin monolayers of reservoir beds with low-reserved capability; (2) the "aggradating platform margin"representative in Longgang area, which is characterized by reef and oolite shoal aggradation and thick monolayers of biodetritus shoal and oolite shoal reservoir beds with high dolomitization, in which excellent reservoirs develop; and (3) the "isolated platform margin" located between Kaijiang-Liangping Trough and Chenkou-Exi Trough where the sedimentary environment was the half-restricted platform during late Permian Changxing phase and became into the evaporated platform during early Triassic Feixianguan phase, which brought ina large scale of reef and oolite shoal deposition and succedent high dolomitization so this kind of margin is the most potential area where excellent reservoirs may be discovered.