A simple method of robot calibration based on laser tracker and least square solution of linear equation is presented. Using the method of linearizing equation,the relational equation between robot end flange position error and link D-H parameter error is established.The robot base coordinate system is established by laser tracer,and each linear equation of joint motor is obtained via the method of circle,then joint twist is solved.At the same time,the robot coordinate values are measured by laser tracker,and six axes angles are obtained through serial port.The real D-H parameters are obtained by solving calibration equation.Then these parameters are used in the kinematics model of corrected system,and to improve the robot's absolute accuracy.In the end,the error and reason of the solution are explained clearly.The reason of robot error is analyzed,and some problems needing attention and improving in the process of calibration are put forward.