The invention provides a fuel-engine-driven compression-absorption combined type heat pump system. The fuel-engine-driven compression-absorption combined type heat pump system comprises a gas compressor, a compressor, a condenser, a condenser, an evaporator, an absorber, a solution heat exchanger, a gas-liquid separator, a generator, a fuel replenishing combustion chamber, a turbine, a combustionchamber, a gas-liquid separator, a four-way valve and a three-way valve. The invention further provides an application method of the fuel-engine-driven compression-absorption combined type heat pump system. The application method comprises the steps that firstly, fuel works in an engine, output shaft work is used for driving the compressor, and steam compression heat pump cycles are implemented through the compressor; heat with the amount being several times that of the shaft work is absorbed out of a low-temperature environment, and the heat and input shaft work release heat into a middle-temperature heat source; and meanwhile, waste heat generated after the fuel works in the engine is utilized, an absorption type heat pump device is driven, the waste heat is input into an absorption typeheat pump, heat absorbed by the middle-temperature heat source, together with the input waste heat, releases heat to a high-temperature heat source through the absorption type heat pump, and therefore, the heat release amount is greater than the heat absorption amount obtained out of the middle-temperature heat source.