Abstract: Daily observations of Shenzhou well often have some sharp pulse,jumps and data missing because of unstable power supply,lightning and other reasons,which is a serious impact on the intrinsic quality of observational data.This paper uses digital signal processing techniques to analyze and process the data of Shenzhou well water level.First,we use piecewise linear interpolation method to interpolate the missing data.Then we use fast Fourier transform spectral analysis on the data of well level,draw its amplitude spectrum,and analyze its different period ingredients.Then by selecting appropriate cut-off frequency for filtering,we successfully get rid of the interference and get well level changes dynamically and improve the data quality.At last,we use the filtered water level data on several earthquake case analyses.