Abstract: In this paper, the authors analized the characteristics of high value anomalies of underground water level, which detected by the Inner Mongolia precursory monitoring network within the limit of 110 km apart from the epicenter of Zhangbei-Shangyi M_s 6.2 earthquake. By using hydrochemistry precursory mark and the judgemenl method, they also studied the relation between high value anomalies of water level and Zhangbei-Shangyi M_s 6.2 earthquake. The judgement scales have been appointed. By using two scales of anomaly frequency accumulation and changing velocity rate, the Zhangbei-Shangyi M_s 6.2 earthquake is tested for the medium-and short term forecast. The occurrence time of Zhangbei-Shangyi M_s 6.2 earthquake accorded with the fundamental result of this paper and it should be pointed out that the anomalies are a precursory reflection for Zhangbei-Shangyi M_s 6.2 earthquake occurred on January 10, 1998.

Key words: Ground water level, High value anomaly, Change velocity rate, Accumulative mark, Zhangbei-Shangyi earthquake