Based on the cave strain observation data in 2013 at the Tai'an station,we use Venedikov harmonic analysis method to calculate cave strain measurement and phase lag of the tide factor,and evaluate qualitatively the stability of the tidal factor for the observational data evaluation. At the same time,the 2 measurement items of the observation instrument are calculated,and the correlation strain parameters are extracted and compared. On the basis of this,the strain parameter time series calculation is carried out on the data quality of Tai'an station,which is relatively stable,and the 2 sets of instruments are compared. Through the analysis,it is found that the stress field is abnormal,and the corresponding relationship between the anomaly of the stress field and the gravity field is compared and analyzed.