Abstract: In order to solve the problem that it is inconvenient for passengers holding China Railway Expresspay Card to recharge offline and reduce the working pressure of station windows, based on the card issuing system of China Railway Expresspay Card, using the key technologies such as terminal MAC verification, and card correction, IDEA and WebStorm development tools, this article designed and built the online recharge system of China Railway Expresspay Card, which implemented the functions of online recharge, inventory and transaction record query. After the system was launched, the market feedback was good, and the proportion of online recharge accounted for 25% of the total recharge amount, and gradually increased.