The Sawuer region is located at the northeastern margin of the West Juggar, where the late Paleozoic volcanic and intrusive rocks are widespreaded. The geochronology and geochemistry of these magmatic rocks has great significance to constrain the regional tectonic evolution in the West Juggar. The Kuoerzhenkuola gold deposit is the most important gold deposit in the Sawuer region. The exposed intermediate-acid rocks in the deposit are range from basaltic andesite, andesite, dioritic porphytite and diorite. The analysis by LA-ICP-MS shows that the zircon crystals from the basaltic andesite have the concordant U-Pb age of 339.4±4.8Ma, indicting that they were formed in early Carboniferous. The Geochemical analysis show that the basaltic andesite and andesite belong to calk-alkaline series, and are enriched in large ion lithophile elements (such as Sr, Ba, Th) and depleted in high field strength elements (such as Nb, Ta). The basaltic andesite and andesite in the deposit have high Th/Yb ratio (0.87～4.84) and low Th/Zr ratio (0.023～0.071). These features are similar to those of the volcanic rocks in the island-arc environment. The primitive magma of the rocks was possibly generated by partial melting of a metasomatic mantle source modified by the subducted slab-derived fluid rather than the slab-derived melt. Geochemical characteristics of the ore-hosted basalt from the Hatu gold deposit in the West Junggar are similar with those of island-arc basalt and N-MORB. The mantle metasomatism induced by the subduction fluid beneath the Hatu deposit is weaker than that beneath the Kuoerzhenkuola deposit. These features indicate the basalt in the Hatu deposit was formed in arc-back basin environment. The volcanogenic hydrothermal gold deposit in the West Junggar can be formed in the island-arc and the arc-back basin.