SCA specifications which provide a uniform and transplantable framework for the exploitation design of software radio are the standard of software radio architecture. Core Framework which mainly performs the function of configuration and management, while provide the core interface and service for the applications of the up layer is the most important composing of SCA specification. The function, composing, interface of the core framework and relations among these are described in this paper, which point out the correct direction for the design of core framework in SCA specifications.