Abstract: Based on the principle of thermology and the system science point of view, the author analysed conception of geocryology thermology and shown the structure of researching method. Geocryo-system can be divided into three levels：geocryo-soil material level , geocryo-layer level and geocryo-region level. Depend on the special properties at every level, the author given the geocryo-system mechanisiously theory. We sure that thermology analysis method shall play important rule in researching the evolution of geocryo-system.