In this paper, the anomalous changes in radon content recorded by nine monitoring sites before ten moderately strong earthquakes occurred along the northern segment of NS seismic zone are analyzed. Further studying the temporal and spatial distribution characters of seismic and aseismic anomalies in the area, total anomaly frequency, time difference between the beginning and ending of anomalies etc., it is found that, in general, the seismic anomalies are characterized by "synchronism" or "cluster" and that the most of "scattered" anomalies are aseismic. Based on the above-mentioned results, the method predicting time, location and magnitude of future shocks using radon anomaly is also proposed.