FDB-type low-temperature cascade refrigeration equipment is a binary cascade refrigeration equipment for national defense scientific research, chemical and pharmaceutical industries and industrial cooling at low temperature, the cooling temperature is generally between -60 ℃ ~ -80 ℃. The entire unit including the semi-closed compressor, condenser, evaporator - condenser, evaporator, filter, oil separator, expansion valve, solenoid valves, intermediate heat exchanger, electric control boxes and other components, assembled into one, the user simply power, cooling pipes and refrigerant pipes can be put into use.