Geological, geophysic and drilling data show that Songliao basin is a Precambrian paleoplate.Nevertheless, in Mesozoic Early Jurassic, the eastern margin of Da Hinggan Mountains and the Songliao tectonicarea remained in an open deep-sea trench environment in West Pacific Ocean, how could a Precambrian paleoplate occur? It is obvious that only through large-scale plate drift could Songliao Precambrian plate be transplanted to Mesozoic deep-sea trench. Therefore, Songliao plate seems to be a large-size allochthon, whereas Da Hinggan Mountains must have been produced as a result of compression and collision between Songliao plate and Mongolia plate.