Abstract: The approach to remote sensing of water vapor based on the global positioning systens (GPS) is described. In order to achieve the best possible retrieved of the vertical integ rated water vapor (IWV) or the precipitable water (PW), the weighted mean temperature of the atmosphere, Tm would be estimated to the specific area and season.Tm depends not only on surface temperature, tropspheric temperature profile, and also on the vertical distribution of water vapor. The surface temperature dependence is born out by a comparison of Tm and the values of surface temperature Ts using radiosonde profiles of Beijing observatory (54511) throughout 1992. The analysis of radiosonde profiles spanning an one-year interval (1992) from sites in eastern region of China with a latitude range of 20～50°N and a longitude range of 100～130°E yields the coefficients a and b of a limear regression equation Tm=a+bTs.