Abstract: Integrating Global Navigation Satellite System (GNSS) and Fengyun meteorological satellite FY-4A can obtain high-precision and high-spatial resolution water vapor distribution information. This paper used the GNSS observation data from crustal movement observation network of China (CMONOC) to carry out the FY-4A water vapor correction study in the Beijing-Tianjin-Hebei region. Firstly, the Beijing-Tianjin-Hebei region was divided into four regions, and the correlation analysis between GNSS precipitable water vapor (PWV) and FY-4A PWV was carried out by regions and seasons. Secondly, different function models were selected by region and season and combined with GNSS PWV data to construct the FY-4A PWV correction models. Then, the GNSS PWV was compared with the results of the regional model and the single-site model respectively to carry out the reliability test of the model. Finally, the corrected FY-4A PWV distribution in the Beijing-Tianjin-Hebei region was obtained through regional FY-4A PWV correction and mosaiced. Research shows that the FY-4A PWV has a good correlation with GNSS PWV, and the accuracy of the regional FY-4A PWV correction model is equivalent to that of the single-site model, which can replace the single-site model for the FY-4A PWV correction. The regional model based on CMONOC GNSS PWV can improve the accuracy of FY-4A PWV to a certain extent, and provide references for the short-term weather forecast and InSAR atmospheric correction.