Based on an analysis of the data obtained from 1:1,000,000 aeromagnetic structural survey, this paper brings forward some new ideas concerning geolo gical characteristics of Alxa area. Some newly-discovered Mesozoic-Cenozoic sedi mentary depression, in particular, provide grounds for further petroleum recon naissance. The division of regional structures in this area and the oil-gas pro spect of the sedimentary depressions are also discussed.