Abstract: Aiming at the low controlling pricy, inefficiency and bad product quality for pre-mill system, a fuzzy-decoupling control system is proposed. Through decoupling, two single-input-single-output channels are created, which make the feeding control the motor current and the rev control the particle size directly, then two individual fuzzy controllers which are current fuzzy controller and granularity fuzzy controller are designed to control the system. The simulation by MATLAB shows that the pr-grinding system static and dynamic properties, adaptivity, and robustness by fuzzy-decoupling control are more superior than that of the conventional PID control. The pre-grinding test on tungsten ore indicates that working stability and product quality of the pre-mill are evidently improved by using fuzzy-decoupling control system.