Abstract: Based on seismometric precursors, the possible scientific basis for the short-term and impending judgement before Zhangbei earthquake (MS 6. 2, January 10, 1998) is dis-cussed. It is important to pay attention to the process from the field to the focus, and transition from middle-term to short-term in precursory anomalies. For the short-term prediction, the seismic gapzoning, quietness, seismic swarm and activity of moderate events, etc. are emphasized, especially, their mutual dependence in time and the physical correlation. Also, the seismometric precursors for 5 earthquakes (M_S≥ 6. 0) happened after 1989 in North China are compared. A new method for anomaly analysis is proposed and the possible function for the short-term precursor prediction is discussed.

Key words: Earthquake prediction, Seismometric precursor, Shortterm judgement, Precursory comparison