Abstract: Using 30a ground humidity parameter data from 94 meteorological stations with empirical equations, this paper calculates and analyzes the spatial-temporal characteristics of precipitable water over Sichuan.And cloud water resources in Sichuan are evaluated as well.It is found that Sichuan is abundant in cloud water resources, which have great potentialities to be exploited.The annual precipitable water and precipitation efficiency in East Basin Area is 1178.11cm and 8.98% respectively, while the annual precipitable water and precipitation efficiency in West Mountain & Plateau Area is 321.06cm and 21.16% respectively.The results show that the spatial distribution of precipitable water and precipitation efficiency is obviously unequal, as the values in West Mountain & Plateau Area is visibly low than those in East Basin Area;that precipitable water in East Basin Area is greatly higher than that in West Mountain & Plateau Area;that precipitation efficiency in East Basin Area is lower than that in West Mountain & Plateau Area.Moreover, precipitable water varies with season obviously, which contributes most in summer (June, July, August), secondarily in autumn, least in winter;and in West Mountain & Plateau Area, seasonal difference of precipitable water is more remarkable.From 1971 to 2000, precipitable water waves with a slight upward tendency and the interannual variation is small.