On the basis of the knowledge of the depositional setting of Maokou Formation in southeastern Sichuan，Combined with outcrop，well log and well logging data，the Maokou Formation is divided into three third-order sequences．According to the research on the lithology,phase sequence and lithologic profile，the sign for identifying and classifying the key sequence surface is expounded，and the characteristics of the every system tracts are summarized．It is believed that the strata at Maokou stage in the study area have the characteristics of rapid tran sgression and slow regression，well sequence comparison and epicontinental platform nature．Therefore，according to the depositional model of epicontinental platform ，the sedimentary facies in the study area can be divided into subtidal low energy zone，subtidal high energy zone，tide flat and lagoon．The sedimentary facies on the vertical and plane profile is described making the system tract a8 unit．Combined with the sequence and the evolution of the sedimentary facies，the depositional model of Maokou Formation is proposed．The beach facies being favorable for reservoir development mainly develops in the high-stand system tract．