Abstract: Based on core and well logging data,this paper made comprehensive study on the characteristics on lithology,sedimentary tectonic,particle size distribution and logging facies and made a conclusion that the block is mainly delta front sub-facies.The main sedimentary subfacies are underwa-ter distribution channel,mouth bar,subsea natural barrier,under water interdistributary and subaqueous crevasse splay.The paper analyzed Chang 6 formation with regional sedi-mentary data,sand body distribution,core subfacies profile and logging profile,received the space and time distribution rule and change rule of sedimentary subfacies,and mean-while discussed the relationship between sedimentary facies and hydrocarbon reservoir.The result showed that the reservoir physical property and oiliness are controlled by sedi-mentary subfacies,underwater distribution channel and mouth bar are main preferable formation,which provided technological support for the further high efficient explora-tion.