Abstract: The Organic source sedimentary depression (sag) theory was on the whole unsuccessful in the process of guiding oil-gas geologic exploration in Junggar basin. This paper discusses the essential reasons for the unsuccess, and then puts forward a new mode for petroleum exploration in this basin: not only regarding the sedimentary depression (sag), but also stressing whether the mantle-derived diapiric structures exist in lower crust or not, both of which should be treated as an inseparable unity. For supporting this new mode, nine evidences are listed. Finally, some ideas or methods for the future work and how to revitalize the potential petroleum resources in 50~60 basins of midwestern China are proposed.

Key words: sedimentary depression, overthrust nappe faulting, mantle-derived diapiric structure, paleo-subducted destructive collision zone