With the continuous development of urban rail transit, the usage of rolling stock in urban rail transit continues to increase, accelerating the consumption of rolling stocks. How to extend the service life of rolling stocks is of great significance for reducing the operating costs of urban rail transit and improving passenger service levels. In the long-term use of rolling stocks, when the maintenance standards are met, rolling stocks needs to be repaired in a timely manner. In this context, how to ensure the balance of rolling stock usage while completing transportation tasks is of utmost importance. Starting from this practical problem, an optimization method is proposed to design an efficient genetic algorithm for problem solving. Finally, taking subway line 3 in a certain city as an example, the calculation analysis shows that the method proposed in the article can effectively ensure the balance of rolling stock usage, thereby extending the service life of rolling stocks.