Abstract: This paper presents a method of robot position error compensation and introduces a high precision positioning system of robot.In this system,a precision measuring device with uncontact sensors is used to obtain the robot position error and a IBM microcomputer is used to collect position error data and calculate the pulses of compensation in each joint.Through the communication interface designed,the computional result is transmitted to robot's control system to realize the compensation of each joint.Transformation between coordinates of the measuring device and the robot hand is obtained by microdisplacement method.And a simple data bank used for error compensation in workspace is built for initial experiment to get the position error value by interpolating and then compensate it.