Affected by Helan piedmont fault and the geological structure in the area, the seismic wave forms recorded by Yinchuan station show distortions, and the distortions cause the azimuth anomaly.

Combined with the data of geological structure in the Yinchuan area, the earthquake azimuth anomalies in the Lingwu Wuzhong area recorded by Yinchuan Station are discussed and analyzed.