Abstract: This study employs the national standard ultra-low frequency vibration apparatus to conduct sensitivity calibration of seismometers, using the 3T-120PH as a typical example. The vibration calibration data are compared and analyzed against the seismometer's transfer function results. At lower frequencies (below 10 Hz), the vibration calibration results show excellent agreement with the transfer function results. However, at higher frequencies (above 10 Hz), discrepancies begin to emerge between the two methods. The vibration calibration method realistically transmits vibration signals to the seismometer, closely mimicking actual usage conditions. Consequently, the shaker calibration method provides a more accurate representation of the seismometer's performance under real working conditions compared to the electrical calibration method. This study highlights the importance of using appropriate calibration techniques for ensuring the accuracy and reliability of seismometer measurements across different frequency ranges.