Abstract: Background and Objective: Perfect and reasonable research on service life prediction of diesel engine can be convenient for users to timely repair and replacement parts, which can avoid the user of the human and material resources of the waste. Materials and Methods: Based on the comprehensive analysis of various factors that influence the service life prediction of diesel engine, this study establishes a mathematical model of the life of military-use vehicle engine, which is based on the cylinder pressure as the main state parameter, the fuel injection pressure and oil pressure as the auxiliary parameters and the other conditions as the correction parameters. Results: Taking a vertical 195 military-use vehicle engine for example, based on the experimental results, it is indicated that the life prediction of the diesel engine by this method is more prolonged than that of the traditional statistical methods. Conclusion: The experimental results show that this method not only has the advantages of convenient operation, saving time and labor but also achieves a personalized treatment for life prediction of diesel engine. It can be known that the service life prediction of diesel engine has great economic value and social benefit. According to the gas clapyron equation established cylinder pressure and diesel engine life mathematical model and consider the fuel injection pressure, the oil pressure and all conditions of use to modify the theoretical model, for the prediction of the service life of diesel engine proposed a more practical method.