The Late Paleozoic volcanic rocks (from Early Devonian to Early Permian) were widely distributed in the south margin of the Altai Mountains. The Middle Devonian Beitashan Formation (Fm.) consists of a series of intermediate-basic volcanic rocks intercalated with more than 100 m thick picritic layer at the bottom, whereas the Middle Devonian Yundukala Fm. is composed of a series of shallow-sea fine-clastic rocks interbedded intermediate rocks and intermediate-basic rocks. The Late Devonian Jiangzierkuduke Fm. includes pyroclastic rocks intercalated with intermediate-basic and intermediate-acid rocks, whereas the Late Carboniferous Batamayineishan Fm. consists chiefly of basalts and basaltic andesites intercalated with tuff, siltstone and carbonaceous shale. On the basis of their major and trace element geochemistry of these four Fms., the Beitashan and Yundukala Fms. include tholeiite and calc-alkaline series, characterized by the enrichment of large ion lithophile elements, and the high field strength element contents close to MORB, which suggest that they formed an arc-island setting. The volcanic rocks of the Jiangzierkuduke Fm. belong to shoshonite series, and is also characterized by relative high LILE enrichment, suggesting the late stage of island arc. Those of the Batamayineishan Fm. belong to alkaline series, characterized by strong enrichment of LILE, implying that they formed in intracontinental plate. Consequently, according to temporal and spatial evolution, it can be inferred that the Late Paleozoic volcanic rocks resulted from the northward subduction of Junggar plate, and the collision between Siliberian plate and Junggar plate occurred at the boundary between Early and Late Carboniferous.