Two-stage cascade refrigeration system of rapid temperature change test box

The invention relates to the field of test equipment, in particular to a rapid temperature change test box two-stage cascade refrigeration system which comprises a first refrigeration system and a second refrigeration system. The first refrigerating system is composed of a first compressor, a first oil separator, a first condenser, a first liquid storage device, a first thermal expansion valve and a first evaporator which are sequentially connected in series through a first refrigerating pipeline piece, and refrigerant of the first refrigerating system is R404A. The second refrigerating system is composed of a second compressor, a second oil separator, a second condenser, a second liquid storage device, a second thermal expansion valve and a second evaporator which are sequentially connected in series through a second refrigerating pipeline piece. The refrigerant of the second refrigerating system is R23. The evaporator of the first refrigeration system of the two-stage cascade refrigeration system of the rap