The shifting drive bearing is a new special type bearing with supporting function as well as speed change function.The design of mechanism is novel and well-knit,with high efficiency and load-bearing capacity.By studying the internal structure and the driving principle of the shifting drive bearing, a group of systematic analysis is made. The theoretical relations of the tooth number of the internal-tooth ring,moving-tooth and drive radio,are provided,as well as the optimum seeking scheme of high efficiency and low wearing and tearing. The conclusion is drawn that the tooth number of moving-tooth should be larger than the internal-tooth ring : Z₂>Z₁. It is very important to direct the design of the moving-tooth drive structure which has push-rod, including the shifting drive bearing.