The invention relates to a wide-area service-oriented data interaction system and method based on a service management center. The system comprises a global management center, a service management center, a service agent, a server side and a client, wherein the global management center is located on a wide area network and monitors and manages all service agents connected to the wide area network; the service management center is responsible for managing registration, positioning and service information of all services in a service domain; the service agent is a unique outlet for realizing inter-domain data interaction and is responsible for transferring service related information between domains; and data interaction is realized by the server side and the client through the service agent. According to the system and the method, the requirements of information interaction between a scheduling control system and a substation in a smart power grid are realized, and the system and the method support interactions between an intelligent device in an intelligent substation and station equipment of other substations, so that complete coverage of information interaction between the smart power grid devices is realized.