Fifteen volume strain observation points were established in Jiangsu province during the construction of the Jiangsu digital seismic precursor network. However, the stability of observation data obtained from these points is influenced by differing installation times, geographical positions, geological conditions, and drilling features. Regression and harmonic analyses have been used in this study to discuss the observed data of volume strain in Jiangsu province; further, the variation characteristics of observed data obtained from different stations have also been analyzed. In combination with borehole histogram and the running status of instruments, the relation among the tidal factor of the M₂ wave, regression coefficients of pressure and water level, lithology, and borehole features are analyzed. In addition, effective measures that can improve the quality of volume strain observation are discussed.