An application of the single-chip microcomputer in the freezedrying system is introduced.The refrigeration system of the freezing dryer is also introduced.The hardware and the software of the control system are designed according to the need of whole system and the demand of each controlled parameter.Fuzzy control is adopted so that the control is independent from the models of treated objects.According to the experiment,it is proved that the control device can meet the engineering requirement without using more precious measuring elements.