Abstract: Abstract: According to the time variation, nonlinear and strong coupling and other features existed in the heavy medium coal preparation process, the fuzzy control theory was applied to establish a control model of the heavy medium coal preparation process.The model was consisted of a modal identifier and three fuzzy controller s and could coordinate with the shunt valve, medium feeding valve and clean water valve. The paper in detain described the structure principle of the fuzzy control model , and the realization method of the modal identifier and the fuzzy control.An industrial operation trial was conducted.The results showed that the fuzzy control algorithm was applied to the medium suspension density and the medium barrel level.The control accuracy could be high, the response speed could be relatively quick, thus the f uzzy control algorithm could meet the control requirements of the production technique.