Abstract: Both the dynamic and static characteristics of the water supply system in watercurtain cooling process in the steel rolling production of Shougang (Group) Company are deeply analyzed. And then a series of practical testing data are acquired, with which a kind of fuzzy model is built based on the composite rule of inference. Finally the simulation test of the fuzzy model is carried out by using GUI in MATLAB, which shows that the model can approximate very well the dynamic response process of the real system.