To comply with China Ⅵ emission standards and Stage Ⅳ fuel consumption regulations， a high-power engine was installed in a commercial vehicle， and it is necessary to optimize the cooling system and enhance its heat dissipation capacity. This paper utilizes the lattice Boltzmann method （LBM） to establish a digital wind tunnel for thermal environment simulations， accurately predicting the vehicle’s heat balance and thermal protection performance， with a coolant temperature prediction error of less than 1 ℃ after comparison between the modelling and experimental data. Based on this， using the coolant temperature of the radiator and the intercooler outlet air temperature as optimization targets， the interactive effects among the condenser， intercooler， radiator， and fan intrusion were analyzed， leading to an optimized design. A simulation process suitable for virtual calibration of engine cooling systems is proposed. The results show that fan intrusion and intercooler height significantly affect the radiator’s heat dissipation performance. After iterative optimization， the air mass flow rate of the radiator and intercooler are increased by 5.01% and 7.87%， respectively， and the surface temperature distribution of the cooling module becomes more uniform， significantly improving the heat dissipation efficiency of the engine compartment.