Abstract: Depositional system analysis is an important part of basin analysis,also, it is the foundation of sequence stratigraphic research, and of important significance for understanding the evolution of the basin. It plays an important role in studying distribution of sedimentary facies, reservoir evaluation and hydrocarbon accumulation. According to the well logging data and core data analysis, the sedimentary system is a complete and typical contraction system domain, the sedmentary microfacies it mainly develops are underwater distributary channel, debouch bar and sheet sand. Combined with the north provenance, the northern sedimentary system decided that the sand bodies in the north region of the study area are more developing. Also, the area that river flowed has a great scale.