The invention provides a nuclear power engine device. The nuclear power engine device comprises a base, a reactor system, an integrated engine and a connecting pipeline, wherein the reactor system comprises a pressure vessel, a reactor coolant inlet, a reactor coolant outlet, a reactor core, a control rod driving mechanism and the like, and the integrated engine comprises an air inlet port, a compressor, a heat exchanger, a turbine and an exhaust port; the heat exchanger comprises a primary-side heat exchange chamber and a secondary-side heat exchange chamber which are isolated from each other; the compressor comprises a front-end coolant compression section and a rear-end air compression section; and the primary-side heat exchange chamber is connected with the reactor coolant outlet and a front-end coolant compression section inlet through connecting pipes separately, a front-end coolant compression section outlet is connected with the reactor coolant inlet through a connecting pipe, and the secondary-side heat exchange chamber is connected with a rear-end air compression section outlet and the turbine through connecting pipes. By optimally designing a front compression section structure, a rear compression section structure, a primary-side heat exchange loop and a secondary-side heat exchange loop, integrated compression and efficient heat exchange of a primary-side working medium and a secondary-side working medium are realized, and the nuclear power engine device is compact, small, safe and efficient.