With the rapid development of science and technology,traditional mechanical drive can not meet the engineering practical needs.Electromechanical integrated piezoelectric movable tooth drive,which has a vital application prospect in fields such as aeronautics and astronautics,micro robot,precitioning etc.,is a new mixed drive which integrates piezoelectric driving,movable tooth drive and harmonic drive and has advantages of larger transmission ratio,lower speed and larger output torque.On the basis of working principle for the piezoelectric movable tooth drive,the forces equations of the drive's elements are established from the piezoelectric nonlinear characteristic and statics relationship of the movable tooth drive.Applying optimization design principle,the design variables,objective functions and design constraints of optimization system are defined,and optimization mathematics models of output torque of the drive system are established.Using numerical method,the changes of output torque of the drive with exciting voltage and rotational angle of tooth carrier are given.The optimized results of output torque are solved by Matlab software.Besides,the parameters changes and output torque with parameters before and after optimization are compared.Results show that a directly proportional relationship is determined between output torque and exciting voltage.The torque is changed periodically with tooth carrier with a period of π/435.The optimized maximum output torque is 0.91 Nm, increased by 111.63 %.In addition,the changing of wave generator offset is largest before and after optimization.So the load-bearing capacity of the piezoelectric movable tooth drive is enhanced.These results provide a basis for modifying the structure and improving performance of the drive.