In order to improve the positioning accuracy of macro parallel platforms,firstly,an error model of 3- RRR parallel mechanism,which takes into consideration the reducer backlash,is derived,and the effectiveness of the proposed model is verified through a comparison with the error model without considering the reducer backlash.Secondly,an experiment is carried out to measure the attitude error of end-effector and to identify the parameters of the two above-mentioned models.Then,IDWM is employed to realize spatial interpolation and error compensation,followed with a kinematic calibration.Finally,the inverse kinematic model is corrected according to kinematic cali- bration results.It is found from the measured posture error distribution of end-effector that the proposed error model considering reducer backlash is superior to that without considering the backlash.The kinematic calibration conside- ring reducer backlash enhances the positioning accuracy of parallel mechanism and provides a theoretical foundation for the development of high-precision macro-micro parallel mechanisms.