In order to solve the problem that a large number tags motion direction judgement in campus long distance attendance system based on 2.45GHz active RFID technology, a technical test system was designed and constructed in this paper, the RSSI of the student tags through the technical test system obtained by two antennas. Then this paper analyzed the data characteristics, and proposed 2.45GHz active RFID card motion direction judgement algorithm based on RSSI distribution. Finally, 1000 student tags are used to experiment, and the experimental results shown that the effective judgment rate of the algorithm reaches more than 99.9%.