The invention discloses an engine-driven cascade heat pump device which is characterized by comprising a cascade heat pump system, at least an engine system and a water loop, wherein the cascade heat pump system comprises a high-temperature circulating system and a low-temperature circulating system; a high-temperature compressor, a condenser, a high-temperature reservoir, a high-temperature throttling valve, a high-temperature refrigerant heater, a condensation evaporator, a high-temperature air-liquid separator and a refrigerant side valve form a high-temperature refrigerant circulating system; a low-temperature compressor, a condensation evaporator, a low-temperature reservoir, a low-temperature throttling valve, a low-temperature refrigerant heater, an evaporator, a low-temperature air-liquid separator and a refrigerant side valve form a low-temperature refrigerant circulating system; and the engine system comprises an engine, an engine cooling heat exchanger, a smoke heat exchanger, a cooling water bypass valve and a fuel regulating valve. The engine-driven cascade heat pump device disclosed by the invention can improve the utilization efficiency of fuel, realize high-efficiency utilization of energy sources, reducing pollution, and realizing multiple functions of refrigerating in summer, heating in winter, preparing domestic hot water and the like with the same unit.