The use of RFID tag which identifies a thing and an object will be expanded with progress of ubiquitous society, and it is necessary to study how to construct RFID network system as a social infrastructure like the Internet. First, this paper proposes the virtualization method of RFID tag network system to enable the same physical RFID network system to be used by multiple different service systems. The system virtualization not only reduces the system cost but also can dramatically reduce the installation space of physical readers and the operation cost. It is proposed that all equipments in the RFID network system except RFID tag could be shared with the conventional virtual technologies. Then, this paper proposes the conditional tag ID processing and the efficient tag ID transmission method which can greatly reduce the processing time and processing load in RFID tag Infrastructure network The conditional tag ID processing allows that tag ID is valid only at a certain time zone of day or in a certain area. The efficient tag ID transmission method uses the virtual network address of the service center as a part of the ID of an RF tag, which allows the direct ID forwarding to the service center.