Carburization is a complex manufacturing process with serious disturbance and time delay,which is multi-variable and uncertain.It is difficult to set up an exact mathematic model.Moreover,by means of conventional control methods and experience,satisfying control result can't be obtained.In this paper,according to the characteristic of controlled-object,Fuzzy control method has been chosen to design a Fuzzy-PI controller and a mixed-PID Fuzzy controller.The result of simulation shows that the robust performance and control result of the new Fuzzy controllers is better than the conventional PID controller.The overshoot is smaller.It is helpful to improve the quality of carburizing workpieces.