The latest drilling and seismic data show that the upper strata of Deng 4,Deng 3 and Deng 2 Members of the Dengying Formation,Sinian (Ediacaran) System are missing in most areas in aulacogen,Sichuan Basin,and only algae-rich layers and the following strata remain in Deng 2,and the Sinian System strata are characterized by annular denudation.The remaining rocks of the Deng 2 Member is mainly silty dolostone,algae laminae dolostone,algal framework dolostone,snowflake-shaped structural dolostone and gravel dolostone.The grape lace structure is developed in some sections,and the sedimentary facies belongs to a typical limited platform,which is the same as that of the Dengying Formation in other areas in the basin,indicating that there is no obvious structural differentiation in the Sinian Sichuan Basin carbonate platform. In this paper,the explanation of the genesis of aulacogen in Sichuan Basin is put forward from the aspects of strata,sedimentary characteristics and tectonic dynamic mechanism.It is considered that the aulacogen in Sinian System was formed after Sinian System deposition,and its genesis may be related to mantle plume arching-stratum denudation-mantle plume collapse and re-settlement.