In order to solve the increasingly prominent performance and safety problems of large-scale legacy systems, and to ensure the reliable and stable operation of the system, the performance and safety status of legacy systems are analyzed and studied, and an optimization strategy is proposed based on this. The optimization scheme is described from five aspects: front-end, database, server, system architecture, and system security. Finally, the optimization strategy is verified with examples. The verification results show that the scheme can effectively improve the performance and security level of the legacy system.