Abstract: Based on the results of core observation and thin section analysis,and analysis of synsedimentary faulting time and changes of relative sea-level in the study area,the Nangang section of the Maokou Formation in Fengcheng Depression,Pingle Depression has been identified as the “breaking Platform” type the depositional environment and sequence stratigraphic framework by the background of siliceous pelitic.“Breaking platform” type sedimentary environment can be divided into 3 types of sedimentary facies,namely the platform basin,the basin margin slope and restricted platform and corresponding three periods.The platform is rapidly stretched and platform basin is slowly shrinking and gradually closed.The sequence stratigraphic framework of “breaking platform” is based on the mutation marine surface(amfs),and the exposure unconformity surface is the top boundary.It lacks low stand system tract(LST)and transgressive system tracts(TST) and develops condensed section(CS),early high-stand system tract (EHST) as well as late high-stand system tract (LHST).The tectonic change is the main controlling factor of the sedimentary differentiation,and the mutation marine surface represents the peak of the synsedimentary fault activity.From the southwest to the northeast,the study area gradually increased,and the sedimentary environment is undergoing the transition from open ocean platform to the subbasin phase,and Fengcheng-Leping area is the central part of the ground.