Abstract: In this paper, based on the study of the geology, geomorphology and seismic activity in the north of Hebei province including Langfang City and itsadjacent region, the result of pattern recognition is obtained by CORA-3 algorithm. The controlled experiment has proved that the result is relatively stable. It has been considered that the positions where earthquakes might occur in the north of Hebei, the potential seismic sources in this region, are related with the activity of NE-NEE, NW-NWW faults. If the activity of these two sets of faults occur in the transition zone between uplift and depression or in a seismic zone, the probability of earthquake occurrence is high. Since the nearly EW fault was formed earleer, the relation of its recent actvity with earthquake is not quite clear.