Provenance analysis is an important way to understand basin mountain evolution. Understanding the provenance of the Upper Permian Xuanwei Formation in the southwest margin of Sichuan Basin is of great significance for reconstructing the evolution of the Late Permian Yangtze Craton perimeter. In this paper, the petrology and whole-rock geochemical analyses of mudstone and sandstone at the top of Xuanwei Formation in the Emeishan area are analyzed, and the provenance, sediment environment and tectonic setting are studied. The mudstone of the Xuanwei Formation is mainly composed of clay minerals with high SiO2 content (average = 49.42%); the sandstone is mostly composed of volcanic rock fragments with small amounts of quartz and feldspar, with moderate SiO2 content (average = 40.12%), and the sandstone belongs to the graywacke. Mudstone and sandstone of Xuanwei Formation have light rare earth element enrichment, heavier rare earth elements are more right-leaning. Compared with the continental upper crust, trace elements are relatively rich in high-?eld-strength elements (such as Nb, Zr) and relatively depleted in large-ion lithophile elements (such as Sr, Ba). Combined with published data on Permian sediments at the perimeter of the Yangtze Craton, it is considered that the source area at top of Permian sediments experienced strong chemical weathering, and the depositional paleoenvironment was an oxygen-rich freshwater depositional environment. The provenance of at the top of Xuanwei Formation not only came from the Emeishan high Ti basalt transported near the source, but also received recharge from the Yangtze Craton. The western margin of the Yangtze Craton was deposited on the active continental margin during the Late Permian.