Abstract: The Penglaizhen Formation in West Sichuan and adjacent areas is thick over 950-1600m,which was deposited during the wilting period of the Jurassic lake basins.Based on the combined demarcation of sequence interfaces and maximum transgressive interfaces,Ⅲ₃ and Ⅲ₄ two sets of sedimentary sequences are classified.By analyzing on the cycles of sedimentary base levels,the sedimentary facies types and apace-time distributive characteristics of the Penglaizhen Formation are discussed,the favorable facies tracts are predicted,and the favorable hydrocarbon-enriched blocks are classified.