Abstract: Plate Tectonics has expounded the material cycle of oceanic crust, and Geosyncline Theory has done that of earth’s surface. Thus a model about the material evolution in continental interior is the necessity for establishing systematic theory of continental geology, and the key to the model is to clarify the genesis of granite which constitutes an important part of the continental crust. The traditional magmatic intrusion hypothesis is not able to hold various data concerning granite. It is a thinking fallacy for the research of granite genesis to use the method of “taking the present as the key to the past” in status of geothermal field.