A rotary MRF (magnetorheological fluids) damper is introduced in tension control systems. An experimental tension control system is designed by using the MRF damper as tension control actuator. Control strategies of the tension control system are studied. A fuzzy-PID feedback controller for the tension control system is constructed and tested, where the variable parameters of the PID were modified by using the fuzzy inference rules. Experimental results indicate that the fuzzy-PID control strategy can be used in the tension control system to get better performance than the conventional PID control strategy.