Abstract: Before West Bao tou MS6.4 earthquake occurred on May 3rd 1996, in the western part of epicenter in Linhe basin, the obvious intensifying and sw arming anomaly of moderate earthquake act ivity appeared, besides, the time sequence of moderate earthquakes is also characterized by concent ration.The five ones among these moderate earthquakes are st rong ly felt so w e paid more at tention to these event s.It is a remarkable medium term anomaly of seismici ty. Unfo rtunately, the main shock w as not near the anomalous area;i t occurred in the area farther aw ay f rom the anomaly point 200 km or so.This phenomenon resulted in our w ro ng prediction of earthquake place.In the paper, the autho r described the details of moderate earthquake activity.In addition to this, by analyzing the tectonics of Linhe basin, the author also discussed the reason w hy main shock occurred farther aw ay from the anomalous place.Undoubtedly, it is of significance in our earthquake predict ion in the future.

Key words: MS6.4 earthquake in West Baotou, Moderate earthquake, Anomaly of intensifying and sw arming, Earthquake prediction