The so-called system integration is to integrate various separated devices (such as personal computers), functions and information into interconnected, unified and coordinated systems through structured integrated wiring system and computer network technology, so that resources can be fully enjoyed and centralized, efficient and convenient management can be realized. System integration should adopt various integration technologies such as function integration, network integration and software interface integration. The key of system integration is to solve the interconnection problem between systems. It is a multi-vendor, multi-protocol and application-oriented architecture. This needs to solve the interfaces, protocols, system platforms, application software between various devices and subsystems, and everything related to subsystems, building environment, construction cooperation, organization and management, and staffing.