This paper discusses the basic parts of the assembly machine,calculate the relationship between torque and axial force,torque and voltage of the piezoelectric transducer.It also analysis the mechanical structure of mechanical.It introduces the motor’s control method .the successful assembly machine is used to assemble the piezoelectric transducer,the experiment indicates that with the increase of voltage, the resonance frequency increases,the impedance is on the decline,the static capacitance remains unchanged basically.And comparison of the assembled and the first assembly piezoelectric transducer,the latter has better performance.