Abstract: Based on the structures and strata characteristics of Xiaoquzi area in Junggar Basin, the study of thermal alternation for three groups of gas source rocks has been made in this paper. It is considered that oil condensate and wet gas may be generated in Lucaogou formation of northern part of the area which made some contribution of natural gas resources to it. While Xiaoquangou group had few contribution duc to mature arca only occurred in the northern part. In late Cretaceous,a great quantity of net gas had been generated in Middle-Lower Cretaceous coal seams located in the pre-mountain seg, and there were nappe frontal faults as hydrocarbon migration pathways, which is an important gas source rock in this area. Therefore,it is concluded that sufficient gas source mainly occurred in northern part, possessing a good fitting between structure-forming period and gas-generating time, and a favorable gas bearing prospectives. Kalaza anticline and the foot wall of nappe frontal fault belong to best structures for gas besring prospectives.

Key words: Junggar Basin, Xiaoquzi area, Gas - bearing prospective, Kalaza anticline, Foot wall of nappe frontal fault