This paper presents a multidiscipline coupled-field analysis method to study the temperature distribution of an automotive magnetorheological brake with double coils placed on side housing. First, a new apparent viscosity definition was employed to connect the communication of magnetic field, fluid dynamics, and temperature field. Then, the dynamic model of the brake was established to evaluated the rotation law of the brake disk and the total brake time. At last, multi-physics modeling was established with sequencetial coupling methods, which were based on the Maxwell equations, Naiver-Stokes equations and conjugate heat transfer equations. The results indicate that the overall temperature distribution of the MR brake is relatively uniform at a zero magnetic field during the steady state, and the maximum temperature difference is about 9.7°C. During braking process, the temperature variation regularity for radial and axial points is basically the similar, and the maximum temperature appears in the axial working gap, the maximum value is 113°C which is less than the maximum allowable working temperature of the chosen MR fluid. The results can be taken as reference to the design of the MR brake.