Abstract: In response to problems that existing drum comprehensive loading test bench cannot complete load test of tractor and automobile on one test bench, a drum comprehensive loading test bench based on disc permanent magnet synchronous motor was developed by adopting series-parallel connection method of changing motor with double winding structure．Drum of test bench has two working modes, low-speed large-torque and high-speed low torque, to meet loading test of tractor and automobile．Finally, a heavy-duty truck and LX2204 tractor were selected to verify loading capacity of test bench, and results showed that designed test bench could complete loading test of tractor and automobile．