Abstract: This paper analyzed the provenance directions of the4th member of Xujiahe formationinnortheastern Sichuan basin using paleocurrent, rock?mineral analysis and heavy mineral methods, and presented the parent rock types in the each provenance area. The study of the provenance directions, sandstone type, debris type and content variation, heavy mineral combination and ZTRindex indicate that the different provenance directions are as follows: in western Yuanba area the sediments are mainly from Longmenshan orogenic belt, the parent rock types are dominated by carbonate rock, followed by siliceous rock and a few low?grade metamorphic rocks; in Tongnanba area the sediments come from Micang-North Dabashan orogenic belt, the parent rock types are dominated by sedimentary rocks, followed by volcanic rock and a few low and mid?high grade metamorphic rocks; in eastern Yuanba area the sediments possibly come from eastern margin of Dabashan area, the parent rock types are mainly sedimentary rocks, secondarily low?grade etamorphic rocks, and characterized by rich feldspars; the middle part of Yuanba area is characterized by mixed provenance. According to the analyses of provenance directions, sedimentary environment, field outcrops, core observation, well logging and seismic data, the northeastern Sichuan basin of the4th member of Xujiahe formation can be divided into three braided?river delta depositional Systems where the microfacies are dominated by braided channels in delta plain and underwater distributary channels in delta front, and the channel sandbody is distributed in the whole area