A system of automatic wheelset tread detection and equivalent conicity calculation based on binocular vision system was proposed, which used laser light source to obtain the tread image of the repaired wheel with the CCD camera. The method of gray processing, filter, edge detection, image segmentation, expansion and erosion was used to obtain the parameter of the wheel. With improving and simplifying the method of equivalent conicity calculation in the UIC 519 standard, the equivalent conicity calculation of the wheelset was realized by combining Simpack with Microsoft Visual Studio software. This system improved the calculation efficiency and accuracy of wheelset equivalent conicity, it helps to optimize the inspection process of the wheelset and ensure the saft of vehicle operation.