Abstract: 5 to 24 days before zhangbei Ms6.2 earthquake (January 10,1998),the geomagnetic low point displacement in daily change (GLPDDC)showed 4 times abnormal in China.In this paper we preliminarily discussed the physical basis of GLPDDC,and briefly introduced the prediction method with GLPDDC anomalies.Through the analysis of the relation between GLPDDC anomalies and the Zhangbei earthquake,we believed that the GLPDDC anomalies before Zhangbei quake were the precursors of the quake.