Strategy of Speed disturbance is used to stabilize an unstable periodic orbits which embedded in the chaotic attractor of chaos in nonlinear torsional vibration model of a planetary gear set. The small speed disturbance control strategy is used for the system that the differential equations are unknown and the allowance of speed disturbance is very small and the optimal parameter control method is used to calculate the speed disturbance in the control procedure. A new method called large parameter perturbation is used for the system that the differential equations are known and the allowance of speed disturbance is relatively big,and the speed is still selected as control parameter. Both the two method control the chaos of planetary gear set to periodic motion state successfully.