Ningqiang MS5.7 Earthquake on May 27,2008,was the largest one in nearly 304 years in Shaanxi provience.Seven days before the earthquake,the data of vertical pendulum,plumbing instrument and extensometer all showed short-term anomalies at Ankang,Baoji,Ningshan and Xi′an stations.The trend of abnormal shape turned point in 2~7 days.Abnormal region lies between two fault belts,which are Lueyang-Yangxian fault and Zhushan fault in south,and Weihe fault in north.The epicenter distances 230~340 km.