The harmonic analysis results of data by the YRY 2 bore hole earth strain meter of Tai an seismic station from 1991 to 1996 are introduced.The dynamic characteristics and stability of the tidal parameters for the meter are analysed. A comparison between the results of the YRY 2 meter and SSY Ⅱ quartz tube extensometer is made. The discrete error mean square of NS channel of the YRY 2 meter is 3.3%, that of NE channel of the meter is 3.6%, and monthly discrete error of phase lag is less than 2.0°. It shows the observation precision of the YRY 2 meter of the station is analogous to the best SSY Ⅱ quartz tube extensometer.