The water level response sensitivity to crustal dynamic process has been proved by the tide water level effect, air pressure effect, and seismic wave records.A series of observation and experiments is conducted to provide the physical basis of reliability for earthquake prediction according to groundwater dynamics.When the mechanical state and external observation environment medium remained constant, changes in the physical properties of the crust medium reveal change in the tidal waves.Therefore, accurate determination of the variation characteristics of tidal water wells may eliminate the importance of tidal factors in the work of earthquake prediction to improve measurement efficiency and also eliminate the utilization of measurement data.Tidal harmonic analysis is an effective method for evaluating the intrinsic quality of well data, which is vital for improving the quality of monitoring data analysis.In this method, digital filtering is used to analyze changes in water level observation data to objectively evaluate the well observation data.Groundwater level in wells is affected by the solid Earth tide, barometric pressure, fault creep, and seismic waves and is thus sensitive to crustal dynamic process.In this study, hourly data was obtained in Dadianzi well, Chifeng, Inner Mongolia, for 156 months from May 2001 to April 2014.The Venedikov tidal harmonic analysis method was used to calculate the tide factor and phase of water level raw data.After eliminating air pressure, rainfall data recorded by the well in Dadianzi were analyzed.The results indicate that tensile stress increased well porosity before the medium-strong earthquakes, which led to this seismic activity.In addition, two cases of wave phase in strong earthquakes are mainly related to phase lag, and the phase of wave interference is eliminated after obvious lag.The M2 wave tide factor and phase in the two cases are very close, which indicated that by using Venedikov tidal harmonic analysis method can reduce the influence of precipitation and the pressure of non-body strain factors on well water level tidal observations to a great extent, which can ensure the reliability and stability of this observation.We obtained good consistency and determined the relevance between tidal factors and phase lag by adopting the Venedikov tidal harmonic analysis method.For well points lacking supplementary observation of barometric pressure and precipitation, we can obtain more reliable parameters such as tidal factor and phase lag by adopting this method to analyze the original data directly.