Abstract: To design the two-tooth difference pushrod movable tooth transmission,the tooth profile equations of the components in mesh pair are derived.The effects of parameters,such as the transmission ratio,half-axis size of cam's theoretic profile and the length and radius of the movable tooth,on the properties of tooth profile are analyzed.Meanwhile,the parameter design condition is advanced according to the desire of no interference appearance on inner gear's tooth profile.By means of the transmission principle and structural characteristic analysis of the movable-tooth-frame,the calculation formula and selecting conditions of movable-tooth-frame's parameters for avoiding the interference of moving parts and meeting the transmission continuity are obtained.On the basis of above analysis,the steps for parameter design of the two-tooth difference pushrod movable tooth transmission are concluded,and a design example is given.The example shows that the geometrical design of the transmission device can be conveniently completed obtained through the presented design steps.