Abstract: Thermomechanical phenomena occurring between sliding plates greatly change the distributions of lining pressure and friction surface temperature of a multiple disc wet brake. It has become one of the main causes of a brake failure. In order to reduce the undesirable thermomechanical effects, several design and material factors influencing on thermomechanical phenomena, such as heat transfer coefficient, friction coefficient, sliding velocity, initial lining pressure and so on, were analyzed, and a new viewpoint - isothermal design method was proposed for designing multiple disc wet brakes.