Magnetorheological fluids are a class of new intelligent materials whose rheological characteristscs change rapidly and can be controlled easily in the presence of an applied magnetic field. Magnetorheological fluids devices used on automobile include dampers,clutchs and brakes. In this paper, the operation mode of magnetorheological fluids devices is analyzed firstly, then introduce the applications of magnetorheological fluids devices in automobil,the application prospects of magnetorheological fluids devices are discussed finally.