The backup modes and specific types of inter-backup system for central control system and district-level dispatch system are introduced. The application conditions, maintenance method as well as the advantages and disadvantages for different inter-backup system are analyzed. The research on inter-backup system for central control system and district-level dispatch system is still at exploring stage in China. The whole structure of this system is simple and reliable. Through the inter-backup between central control system and district-level dispatch system, the resources of central control system and district-level dispatch system are used furthest, and the security is improved. The system will be applied broadly in future.