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 medium SiO₂ content (average 49.42%); the sandstone is mostly composed of volcanic rock fragments, containing a small amounts of quartz and feldspar, with medium SiO₂ content (average 40.12%), belonging to the greywacke series. 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 field strength elements (such as Nb, Zr) and relatively depleted in large ion lithophile elements (such as Sr, Ba). Combined with the published data of Permian sediments at the perimeter of the Yangtze Craton, it is considered that the source area of sediments at the top of Permian Xuanwei Formation experienced strong chemical weathering, and the depositional paleoenvironment was an oxygen-rich freshwater environment. The sediments at the top of Xuanwei Formation not only came from the Emeishan high-Ti basalt transported near the source, but also supplied by the Yangtze Craton. The western margin of the Yangtze Craton was deposited on the active continental margin during the Late Permian.