Abstract: The pressure sensor tide gauge is the main auxiliary sensor in bathymetry, which is mainly deployed in the medium-short tide gauge for the water level control of coastal bathymetry. Therefore, the sounding precision can be greatly restricted by the irregular drift of the zero point of the pressure sensor tide gauge in different operating environment, and the related detecting and correction theory are scare and lag behind. The formation mechanism of the irregularly drift has been analyzed in this paper, and the detecting method and calibrating model have been brought forward. Furthermore the observed data of one month between the long-term tide gauge Dinghai and the temporary tide gauge Gangxin have been analyzed. The results show that the vibration of the partial tide with different pe-riods can be weakened by two kinds of daily mean sea level calculation methods. The calibration model can be effectively applied in the processing of the zero point of the pressure sensor tide gauge and the observation precision can be improved from more than ten centimeters to centimeter.