Abstract: The influence of underground water to the leveling observation should be eliminated when the observational data are used for quantitative analysis. According to the action mechanism of underground water to ordinary bedrock mark and the situation of laying steal pile mark, we need to change the data of underground water firstly and define the interaction coefficient. Then to deduce calculus formula of underground water acting to West mark and calculate it. Finally to eliminate it from high-contrast in West-North level. This way can explain the reason why Jinzhou station leveling is affected by underground water during the different stages, and can quantitatively remove disturbance from underground water. It can acquire abnormal information from high-contrast result of leveling observation and can improve the application value of leveling observation data in earthquake prediction.

Key words: Underground water, Leveling observation, Influence correction, Anomaly analysis