Through the analysis and research at the end of the Z axis of the direction of rotation of the attitude adjustment of microassembly,an easy and simple method on accuracy of measurement and returned gap of the rotary motor was presented.The concrete step of experiment was designed.The experimental data show that using this method can meet the measurement of high precision rotating of stepper motor and calibration.The foundation is laid for ensuring precision assembly of small parts and for the rotating operation of the end effector of microassembly.