An RFID reader having a multi-dimensional antenna array makes use of electronic circuits to change the antennas or coils of an RFID device to form a multi-dimensional antenna array, thereby accomplishing detection of the ID codes of RFID tag devices in a scanning way of the RFID technology. This scanning method can also actively discriminate the locations of RFID tag devices. The RFID reader having a multi-dimensional antenna array can scan a plurality of RFID tag devices, and can also effectively discriminate the locations of these RFID tag devices.