Abstract: Global calibration is a very important part of data fusion for multi-vision in large-scale detection system. Through the specific structure of binocular stereo vision target plate, under the premise of completing binocular stereo vision calibration, the global calibration under multi-vision is completed by laser tracker and related vision algorithm. The technology is applied to the scene of key dimensions detection of large-scale railway passenger car body. Through experimental analysis, the global calibration algorithm has good robustness and improves the large-scale rail. The field adaptability of key dimensions detection of bus body can improve the detection efficiency and accuracy.