The kinematics model of the robot is analyzed according to the generic robot unified robot description format (URDF) file on robotic operating system(ROS). To simplify the kinematic model, some constraints are set for easily extracting of the calibrated parameters. Since the calibration model has multiple parameters and robot′s non-geometric parameters have poor effect on the robot′s accuracy, a method of fractional steps combined screw-axis measurement identification method and Kalman filter calibration method is proposed. In order to verify the feasibility of the method, simulation and experiment are made respectively through Matlab and laser tracker. The calibration results of baxter robot show that the method mentioned can obtain a more accurate kinematic geometry parameter. It can be applied to the robot built on ROS or ones with large joint compliance.