Abstract: Upper Permian Longtan Formation coal-bearing strata in southern Sichuan region is characterized by the depth and thickness variation.Guided by the theories and methods of the Sedimentary petrology and sequence stratigraphy,through consolidated results of previous studies,the authors divided the Upper Permian Longtan Formation in the Shibao ore block of South Sichuan into 3long-term sequence (LSC1-LSC3) and many medium-term sequences through comprehensive study of outcrops,coring,logging and seismic data.According to the identified four kinds of sequence boundary and its manifestations substances,including regional unconformity,fluvial erosion surface,lithology,lithofacies conversion surface and maximum flooding surface,the long-term base-level cycles in each cycle of the material change and mechanism of coal accumulation has been described.By multi-well sequence stratigraphy contrast,isochronous stratigraphic framework has been established that has important implications for coalbed methane exploration and mine development work Shibao ore block.