Abstract: Using the ground-based GPS-retrieved atmospheric Precipitable Water Vapor(PWV) data of JICA Program and the ground data from automatic station in Sichuan from January,2010 to December 2011,it analyzes the characteristics of GPS/PWV in Sichuan.The results show that:GPS/PWV can be used to reflect the seasonal characteristics of precipitation,altitude has a significant effect on GPS/PWV values,the average GPS/PWV value in the nighttime is greater that in the daytime,the average GPS/PWV value in the nighttime is less than that in the daytime in autumn in plateau;in the main flood season,GPS/PWV can used to be the criterion to judge whether the precipitation occurs or not,precipitation appears in the period of the PWV values greater than the reference value;the variation periods of PWV and precipitation are also identical,with the precipitation starting mostly following the peak after a consecutive increasing of PWV,the large increasing amplitude or keeping at high level of PWV can be used as an indicator for forecasting continuous heavy precipitation.