An RFID (Radio Frequency Identification) tag includes a grounding casing, an coupling casing disposed opposite to the grounding casing and an RFID module. The coupling casing includes a coupling part cooperating with the grounding casing to define a coupling space there-between. The RFID module is disposed in the coupling space and includes an RFID chip and a coupling member coupled electrically to the RFID chip such that upon receipt of one of the driving signal and the identification signal, surface current is generated on an upper surface of the RFID tag, which, in turn, induces a resonant electromagnetic energy within the coupling space, thereby increasing a detecting strength of the RFID module relative to the one of the driving signal and the identification signal.