An accurate patient positioning method in radiotherapy based on binocular vision photogrammetry is described in the paper.The patient’s images taken by two calibrated cameras from different points of view are reconstructed in stereo

then the difference of three-dimensional coordinates between the referenced and real-time positions of the patient’s focus is figured out to resume the planned radiotherapy position.The experiment shows that the three-dimensional coordinate’s difference between the referenced and real-time positions can be measured accurately.