Abstract: The Late Carboniferous intrusive rocks in Orqohan area are closely related to the polymetal minerogenesis of Derbugan metallogenic belt. The forming environment and mechanism of the rocks are discussed by studying on the geological and geochemical characteristics of Banlashan series. It is concluded that the intrusive rocks of Banlashan series are evolved from the mixed materials of meanly mantle source, and intruded in subduction area.