Abstract: In order to investigate meshing force of the swing movable tooth transmission actuated by cam,academic and work tooth profile equations of the central inner gear are deduced based on its transmission principle.According to the suppose of stretch small distortion and distortion congruity,the model and algorithm of meshing force analysis under theoretic meaning are proposed,the presented method is illuminated through an example of meshing force calculation,and the distributing tendency of meshing force of this type of transmis- sion device is assumably acquired.