Abstract: In order to investigate the reliability of the observation of precipitable water vapor in the Tibetan Plateau, this article compares and analyzes five different observations collected at Naqu, Gaize and Shenzha from June to September 2015. Observations include the GNSS PW, the radiosonde PW, the FY-3 visible infrared scanning radiometer sensing data (FY-3 PW), the MODIS remote sensing data and the NCEP gridded reanalysis data (NCEP PW). The result shows that the radiosonde PW and the GNSS PW are closed with the differences less than 2.5 mm. FY-3 PW is significantly drier than the other observations, and the biases are larger than 6 mm.The degree of dispersion for precipitable water vapor observed by the automatic sounding systems at Gaize and Shenzha stations is obviously larger than that by the L-band electron radiosonde at Naqu Station, and the RMSE is larger than 4 mm.