In order to understand the material source, tectonic environment and basin characteristics of the Early and Middle Jurassic period in northwest Sichuan Basin, field geological surveys of the Early and Middle Jurassic strata, whole-rock geochemical analysis and zircon U-Pb dating of sandstone were used to investigate the sedimentary characteristics, sedimentary environment, terrigenous clastic characteristics and tectonic setting recorded near the orogenic belt. The results show that the sedimentary environment in the early and middle Jurassic of the western Sichuan region is characterized by alluvial fan-braided river-alluvial fan-fan delta. Multiple geochemical indicators indicate that the weathering intensity of the samples from the sedimentary period of the Shaximiao Formation in the study area is moderate, and the geochemical indicators can reflect the characteristics of the original sediments. It is concluded that the main source rocks in the study area are felsic volcanic rocks in the acidic source area under the background of the continental island arc. The source areas of the Qinling orogenic belt and Micangshan-Dabashan may affect Guangyuan area, while the source areas of the Songpan-Ganzi Terrane, Yidun Island Arc and Kangdian Paleoland may affect the Chengdu area. The Jiange area may have received mixed input from the Songpan-Ganzi Terrane, the Qinling orogenic belt and the Micangshan-Dabashan source areas. The differential uplift of Longmenshan might be the main factor in the spatial allocation of the source areas.