In order to improve the performance of Luotuo LR6105 explosion-proof diesel engine, the numerical simulation method was used to model and simulate the whole machine. The numerical simulation results were compared with the experimental results, and the results in good agreement, indicating that the model with certain reliability. Based on the change of injection timing and intake pressure, the influence of injection timing and flame arrester on engine power was studied, which provided a basis for optimizing the performance of explosion-proof diesel engine.