How to improve the fusion accuracy of measurement range and multi-position measurement data is the key to realize high precision measurement of large components. A mobile robot tracking measurement visual tracking system based on photogrammetry is designed to realize the fusion of multi-position measurement data with large precision and complete the measurement of high-speed train body. Specifically, aiming at the problem that the high-speed train body size is up to 25m×4m×4m and the range of single measuring equipment is limited, this system realizes the measurement of a wide range of the system through the robot grasping structural light equipment and guide rail to move the robot. In order to achieve high-precision measurement data fusion in multi-position pose, the system uses multiple monocular cameras to track the movement of measurement cameras, realizing rapid measurement data in multi-position pose and accurately aligning the tracking data to the same coordinate system. The system and laser tracker T-Scan measuring system are respectively used to measure the size of the door, and the experiment verifies that the measuring accuracy of the designed measuring system is equivalent to that of the laser tracker T-Scan measuring system.