Abstract: Natural gas reservoir-formation condition of Shaximiao Formation in mid-band of Western Sichuan Depression was discussed in order to provide evidence to explore oil and gas. Source rocks, reservoir, preservation, and play were analyzed combining with structure history, rock core data, seismic data and drill data, the result indicated that the mid-band of Western Sichuan Depression was located in the center of hydrocarbon producing zone and source rocks developed widely here. In the mid-late of late-Triassic, alluvial fan and fluvial deposition developed and fault breaks developed in the late of late-Triassic which was good for gas accumulation. Preservation is good because pressing boxes and thick sand shale imbedded upon reservoirs. Palaeohigh of EW direction in Xinchang-Yanting area in mid-band of Western Sichuan Depression and Yazi River-Shibantan area in spread deformable zone in front of Longmen Mountain are good belts for oil and natural gas exploration.