Abstract: This paper presents the precursory anomaly of underground water temperature and the water level in Wuliying well before the Zhangbei-Shangyi earthquake, on January 10, 1998, and the co-effect and after-effect of the earthquake. The main characteristics are that the precursory anomaly of underground water temperature and level appeared at the same time and their trends were in reverse direction before the earthquake. After the earthquake the trends are changed into same direction. This phenomenon is unique in the underground fluid comprehensive observation.

Key words: Water temperature, Water level, Precursory anomaly, Zhangbei earthquake