Abstract: The relationship between underground volcanic structure and Carboniferous gas reservoir in Kemaleili gas field of Junggar basin was analyzed. The results show that there are three central eruption underground ancient volcanic structures in this area. The eruptive centers of them are located in Dixi?8, Dixi?27 and Dixi?10 well areas. In the central eruption ancient volcanic structure, the subvolcanic rocks and proximal facies lava near the crater have better reservoir property and more developed fractures as well as relative high structure location, which are the favorable zones of the oil and gas migration and accumulation. The overlapped tuff/sedimentary rocks and lava/subvolcanic rocks provide good lateral sealing conditions for the gas reservoir, being beneficial to the gas accumulation.