Xujiahe Formation in western Sichuan Depression is one of the main gas producing horizons in Sichuan Basin.Based on the analysis of core observations，drilling and well data，it is considered that four sedimentary microfacies including underwater distributary channel，estuary dam，distributary bay and sheet sand are developed in the Upper 4th Member of Xujiahe Formation. Combined with common/cast thin section observations，scanning electron microscopy and X-ray diffraction，the diagenetic facies and tectonic facies of the reservoirs are studied in depth，and the diagenetic facies is divided into compacted facies，carbonate cemented facies，dissolved facies，kaolinite-corrosion facies，and carbonate cemented-corrosion facies，tectonic facies is divided into fracture facies and non-fracture facies. By comprehensively considering the influence of sedimentary，diagenetic and structural factors on the reservoir，the petrophysical facies of the reservoir in the Upper 4th Member of Xujiahe Formation is divided into five types including Ⅰ，Ⅱ1，Ⅱ2，Ⅲand Ⅳphysical facies. Among them，TypeⅠis a high-porosity matrix-fractured reservoir，Type Ⅱ1 is a high-porosity matrix reservoir，Type Ⅱ2 is a lowporosity matrix-fracture reservoir，Ⅲis a low-porosity matrix reservoir，and Type Ⅳ is mudstone. Based on the logging data，the logging criteria of various rock physical phases are established to provide a basis for the establishment of a single well petrophysical facies.