In this study, a beta-type 500-W Stirling engine is developed and tested, and a nonideal adiabatic model is built and applied to predict performance of the engine. Engine torque, engine speed, and shaft power output are measured under various operating conditions. Furthermore, as the charged pressure and the heating temperature are set at eight bars and 800 °C and a No. 50 wire mesh is used in the regenerator, the shaft power of the engine can reach 556 W at 1665 rpm with 1.21-kW input heat transfer rate (45.95 % thermal efficiency). The experimental data are compared with the numerical predictions to verify the theoretical model. It is found that the experimental data of the shaft power output closely agree with the numerical predictions. This implies that the theoretical model is valid and helpful to the engine design.