According to the measurement requirements of the train wheelset measuring instrument,the whole hydraulic system was designed. The control sequence of the wheelset hydraulic system was analyzed, and the 7 hydraulic cylinders in the mechanism were reasonably arranged,including left/right jacking, the left/right lifting, the left/right shifting fork and the friction wheel feeding hydraulic cylinders. The main parameters of the hydraulic system were calculated, and the components of the hydraulic system were reasonably selected. The whole control circuit was designed and the synchronous circuit of the lifting mechanism was designed. The hydraulic system has been in operation for 3.5 years. The results show that the pressure loss of the hydraulic system is within the proper range. The hydraulic system works normally and stably during operation.