Abstract: The vision system is the main sensor of RoboCupF180 small size soccer robot system,which is used to collect information from the environment.In order to improve the real-time performance,accuracy and robustness of this vision subsystem,this paper describes a new pattern design,and the reliability of current information is calculated from the previous information.The Tsai's method is used to calibrate the camera and its distortion,which improves the recognition rate under variable lighting condition and increases the positioning accuracy of the robots and the ball.The vision sub-system is tested in the real competition.