Abstract: Objectives This study proposes an integrated simulation method for marine power systems combining propeller hydrodynamic characteristics with diesel engine thermodynamic properties, aiming to reveal the influence of wave disturbances on system performance. Methods The SST k-ω turbulence model and Volume of Fluid (VOF) method were employed to analyze free surface effects on propeller open-water characteristics. A Seiliger-cycle-based mean-value engine model simulated steady/dynamic operations of the main engine, obtaining thermodynamic parameters. The integrated power system model investigated dynamic responses during ship acceleration in waves. Results Under rough sea conditions, wave-induced thrust losses reached 18.34%, significantly affecting propeller output stability and navigation safety. During acceleration, exhaust temperature and excess air coefficient exhibited severe fluctuations peaking at 1,370 K and 0.5589 respectively, exceeding the engine's safe operational limits. Conclusions The proposed method accurately predicts dynamic performance variations in waves by coupling hydrodynamic and thermodynamic models, revealing parameter interaction mechanisms. Combined with operational boundary analysis, it provides theoretical support for developing control strategies under extreme sea conditions.