Abstract: Camera calibration is an important element in the application of vision robot.A method of the exterior parameter self-calibration was presented for the robot vision system with a fixed camera.The basic principle of the proposed calibration method is to control the robot end undergo three sets tiny motions along three axes of the base frame respectively,then use the image information grabbed by the calibrated camera to calculate the exterior parameters based on the relationship between the camera matrix and the matrix of the robot end to the robot base frame.Moreover,taking into account the effect of measurement and calculation noises,an orthonormalizing adjustment was also given to correctct the calibrated rotation matrix's orthonormality and error.The method is proved to have a good performance of accuracy and robustness,and is feasible of on-line camera calibration with some experiments on synthetic and real image.