In order to apply the movable tooth drive in precision drive field, a mini type large transmission ratio movable tooth system is designed. Based on an elastic dynamic theory of planetary gear drive, the dynamic model of movable tooth system is established. Considering the nonlinear effect caused by the changing of meshing tooth number, the nonlinear dynamic equations of the movable tooth system are built.The nonlinear amplitude-frequency relationship and resonance equations are deduced with the harmonic balance method and the the perturbation method. Besides, the amplitude-frequency curve changes with parameters and the resonance response laws under different multiplicity frequency are analyzed with the two sets given parameters. Results show that the damping coefficient ζand the amount of meshing movable teeth f have a large impact on an amplitude-frequency curve, and the system resonance is prominent whenωe≈ω1 andωe≈1/2ω1. So, in order to reduce vibration and improve stationarity of the system, a small number of the movable tooth and small offset of wave generator is necessary. The results lay a theoretical foundation for modifying the structure and improving transmission efficiency of the movable tooth system.