Abstract: In this paper, by studying precursory data of large range before Baotou earthquake (Ms6.4), the Authors suggested that anomalies group of precursor field may appear with different fea-Tures before a strong earthquake in different areas around the epicenter, The main char-Acter of the near field (△≤100 km) is a tendency anomaly with relatively long time scale;the main character of the middle-far field (100 km < △≤200 km)showed both tendency and sudden anomalies, but the distant field, generally speaking, showed no anomalies, only showed short term and imminent prexursors of the earthquake.