Abstract: Owing to the fact that the use of conventional PID controller is unable to meet the requirements for adjusting the controlled parameters, a control model based on fuzzy control algorithm is proposed.The fuzzy inference model is designed according to the coupling phenomenon of a multiple of characteristics, including time variability and nonlinearity of multiparameters generally observed in currently used mainstream coal washing process, as well as the practical experience of experts. A study of the self-adjustment process of parameters involved in the heavy medium suspension density control system is also made. As evidenced by study result, the use of the fuzzy PID control method can lead to effective reduction of the quantity of overshoot parameters, increase of response speed, cut of adjusting time and enhancement of dynamic performance of the system.