Abstract: There are abundant natural gas resources in Xujiahe Formation in Xinchang-Hexingchang in western Sichuan Basin, with proven reserves of 1700×10⁸ m³ in Sinopec exploration blocks. The reservoir is characterized by “one-deep, two-high, and two-low”, including great burial depth of gas reservoir (4500-5500 m), high formation pressure (pressure coefficient of 1.4-1.7), high fracture pressure (110-165 MPa), ultra-low porosity (average of 3.7%), and ultra-low permeability (average of 0.07 mD), which brings multiple challenges to geological theoretical understanding and high-efficiency gas development, and restricts the progress of exploration and development. Based on the research idea of geology and engineering integrated practice, understanding of tight sandstone gas migration and accumulation has been deepened, and gas accumulation mechanism and enrichment and high-yield production laws have been identified. By starting from the detailed analysis of development mode of geological sweet spots, the formation mechanism of gas reservoir sweet spots has been determined, and a sweet spot geological model has been established. By applying fracture and reservoir fine seismic characterization and quantitative prediction technology, and optimizing drilling and reservoir reconstruction technologies, the geology and engineering integrated collaborative research on key technologies such as geology, geophysics, drilling and completion has been conducted, and the practice of technology and economy integration has been implemented. The successful application of technical sequences supports the large-scale production of the gas field, with a cumulative production capacity of over 10×10⁸ m³, and new addition proven geological reserves of 1300×10⁸ m³ in Hexingchang Gas Field, which further confirms that the integration of geology and engineering is a necessary way for the effective development of low-grade gas reservoirs, promotes the beneficial development of Xujiahe gas reservoir in western Sichuan Basin, and provides reference for the exploration and development of tight and difficult to use reserves, especially deep tight gas.