The OAI(Open Archives Initiative) is an evolving protocol and philosophy regarding interoperability for digital libraries. This protocol has its roots in an effort to enhance access to digital libraries as a means of increasing the availability of scholarship communication. Thus, this research outlines the history of the OAI protocol, the basic model of SP(service provider)/DP(data provider), and the prerequisites to implement the OAI protocol. Viewed in this light, this paper also describes the experiences of KERIS project of SP/DP model and lists the differences between prerequisites and KERIS case.