This paper presents a self-adaptive fan clutch for automotive application using MR fluid and SMA. Based on Bingham model, the equation of transmission torque developed by the MR fluid for fan clutch is derived. A SMA spring actuator is designed to control the angular velocity of the fan clutch. The characteristic of output angular velocity is studied in detail. The results indicate that, the change of temperatures has a tremendous influence on the output angular velocity characteristic of the fan clutch, and output angular velocity of the fan clutch can meets the demand of engine cooling fan satisfactorily.