All the components of our parallel hydrodynamic retarder shell, stator and rotor, filter element, etc. have completed the sample development, the design of controller, application programme, etc. has been completed, and the test stand has been built successfully. The hydrodynamic retarder test stand consists of 600V power supply cabinet, 400kW motor, 12-speed commercial AMT, hydrodynamic retarder, 12bar gas source, cooling tower, etc., which can carry out the fatigue and durability test of hydrodynamic retarder.