The RFID framework constructed by Reader, Transponder and Middleware system forms a new construction of future production line automation, material management and logistic industry. The EPC (Electronic Product Code) Network, advocated by international organization, EPCglobal Inc., is the standard technology of RFID application. This paper proposes a cross layer design that applies an intelligent mobile purchasing system by combining RFID smart phone at Physical layer, transferring the RFID code into EPC Network at Media Access Control Layer, gathering the EPC Domain Information at Application Layer and establishing the secure EPC network framework with Product of Authority Server (PAS) network environment at Application Layer. By using the cross-layer approach, user can purchase through the smart phone with RFID Reader. Content Web Server and ODS Server are responsible for recording the commodity information by EPC Code. The commodity will be directly sent to user's home through the Object Tracing Function of Secure EPC Network.