The PWV data of GPS/MET from May to September 2012, the automatic rain gauge data and the radiosonde data are analyzed. The results are as follows: (1) There existed high correlation and small errors between GPSPWV and radiosondePWV measurements observed at the same station, but less obvious correlation when there was rainfall. (2) GPSPWV values were about 10 mm lower on plains than in hilly areas when rainfall. (3) 69% of GPSPWV values rose before a storm appearing, and in the cases of not rising, the GPSPWV reached a higher value. When the GPSPWV values of 6 hours and 12 hours were positive, it is indicated that rainstorm will start. (4) GPSPWV characteristics were different under different types of rainstorms: the storm centers of local rainstorms caused by the westerly system and subtropicalhigh in Hubei Province correspond with GPSPWV high values, with the GPSPWV threshold values being less than 40 mm and 55 mm, respectively, in west of Hubei Province and the GPSPWV threshold values being less than 52 mm and 60 mm, respectively, in mideast of Hubei Province. The local rainstorms affected by Typhoon usually lie around the dense zones of GPSPWV nearby the high values area, with the threshold values less than 45 mm. During heavy rain processes, GPSPWV high value centers appear 1 hour earlier comparing with the heavy rainfall centers under favorable weather conditions. (5) There were three kinds of situations in which storm centers locate in GPSPWV dense zones: rainstorms caused by a fastmoving storm systems, local rainstorms affected by a Typhoon, rainstorms in mountains areas. (6) It can be indicative of rainstorms very well in the mideastern Hubei Province, but poor in the mountainous area of the western Hubei, while comprehensively considering GPSPWV high values and ground convergence zone 1 hour before.