Abstract:According to the GNSS precipitable water vapor(PWV), we carry out accuracy evaluation and correlation analysis of MODIS PWV in southwest China, construct the regional correction model and single-site correction model of MODIS PWV, and carry out a reliability test. After sub-regional MODIS PWV correction and image superposition, we obtain the corrected MODIS PWV distribution in southwest China. The results show that the regional model can be used to replace the single-site model, and the seasonal correction model of MODIS PWV in southwest China has a significant effect. The root mean square error(RMSE) in spring, summer, autumn and winter are better than 8 mm, 9 mm, 11 mm and 4 mm, respectively.