Abstract: Based on the significant energy loss in the exhaust gas of the JetCat 16-kilogram micro-turbojet engine, this paper proposes a design method using this engine as the gas generator, followed by an S-shaped connecting pipe, a guide vane, and a power turbine. Under the inlet conditions of relatively low total temperature and total pressure, this design method achieves an output power of 29.84 kW. The core of this research is to develop a power turbine with a maximum radial diameter of 118 mm and use it as the core component for energy recovery. The feasibility of this design method was verified through the overall performance calculation of the micro-engine, the design of the two-stage axial flow turbine, the grid independence test and the numerical simulation analysis. The overall performance calculation results show that the deviations of thrust, fuel consumption rate and fuel flow from the engine performance requirements are all less than 3%, meeting the performance requirements. The numerical simulation results of the power turbine show that the efficiency of the turbine stage can reach 87.28% and the drop pressure ratio can reach 1.5, meeting the design requirements.