The opinions to the sedimentary facies in the western Sulige gas field were so different that they lead to the big difficulty to forecast the sandbody distribution in exploration and development. We studied the sedimentary facies through adopting the techniques and methods of stone characteristics analysis, sedimentary structure description, and fossil observation; revealed sedimentary sequences of outcrop from Chengjiazhuang based on the facies logging and seismic reflection related to fluvial facies researched by predecessors in the Lower He_8 Member. The research results show that the braided river deposition is the main facies type of the Lower He_8 Member in Western Sulige Gas Field. In our opinion, the frequent climate change from dry to humid is the controlling factor,which resulted in the large thickness of sandbody, strong heterogeneity, and lateral variation of reservoir.