Abstract: Many studies are starting to use GPS technology in meteorology. This paper introduces the principle of GPS detection of atmospheric water vapor and the scheme of atmospheric precipitable water vapor (PWV) retrieval from ground-based GPS.Atmospheric PWV retrieval using GPS data from 2008 July to 2010 December from the Hubei GPS observation network was combined with ground observation data. This paper analyzes winter fog from this period. Synthesized GPS-PWV data and visibility for foggy and clear conditions were analyzed. The diurnal variation and spatial distribution characteristics of GPS-PWV in winter fog in Hubei are shown, and daily variation of GPS-PWV of foggy and clear conditions are contrasted. A prediction equation is established based on linear regression between GPS-PWV data and conventional meteorological data. This equation is then tested and used to analyze fog forecasts for year 2011. This paper offers valuable reference information for short-time forecasts of the heavy fog.