Abstract: The heating system of TH-FD55× 2 food vacuum freeze drying machine uses the saturated steam as the heating source, the heating medium is input through the hollow plate in the radiation heating manner, the heating medium tank is used to store energy and stabilize pressure, the three-way control valve and the plate heat exchanger are used to accurately adjust the temperature of the heating plate . The system has the properties of well-distributed heating, high heating efficiency, accurate temperature controlling and high reliability.