Abstract: An analysis of the observational data variation characteristics of the Gaotai borehole strain instrument reveals that the YRY-4 borehole inclinometer has provided continuous, stable, and reliable data over the past nearly 18 years of operation. These data accurately and objectively reflect the changes in crustal stress in the Gaotai area, providing precise and trustworthy data support for geophysical and earthquake prediction research. Furthermore, the observational results indicate that both the principal azimuth angle and principal strain of the Gaotai borehole strain exhibit a trend of tensile state, particularly with the tectonic principal strain showing a long-term tensile trend from west to east. Additionally, the maximum and minimum principal strains of the Gaotai borehole strain also demonstrate a certain annual variation pattern, characterized by periodic expansive and contractile changes.