In order to realize the precise positioning of radiation patients and the accurate measurement of tumor location in the process of precise radiation therapy,a med ical robot positioning system based on binocular vision is established.First,the medical robot positioning measurement system is developed based on binocular vi sion; Secondly,based on the Tsai camera model and the influence of lens distortion,a new camera calibration method based on planar and three-dimensional checkerboard calibrati on templates is proposed to get the camera calibration parameters; Thirdly,the center point po sitions of markers are identified and their three-dimensional coordinates are calculated based on the robert gradient operator method for image segmentation.Finally,the measurement errors of all markers by binocular vision and the three-dimensional coordinate measuring instrument a re used to achieve the position-validating for radiotherapy patients.The experimental results sho w that the camera calibration accuracy is 0.0365mm and three-dimensional coor dinates′ average deviations of each marker are δX=0.573mm,δY=0.495mm,δZ=0.430mm.The measurement method can improve the accuracy of calibration and positioning,and meet the clinical re quirements for high-precision positioning system in precise radiotherapy.