Tension control is widely used in industrial production. This paper gives one tension control method using MRF damper as the actuator. The principle of the tension generation is introduced. Through analysis and numerical simulation, the main influence factor of tension changing is obtained. The result of simulation shows that the influence factor of the tension includes the excitation electric current of the MRF damper, the radius of a wheel, rotate speed, the fluctuation of the rotate, etc. These factors present strongly nonlinearity. Through controlling the excitation electric current of MRF damper, the fluctuation of tension can be controlled to decrease.