Abstract: Water is a lifeline in arid and semiarid area.Artificial precipitation is an important method to increase water resource.Based on water vapor pressure of four real times and daily precipitation data from 1971-2000 recorded by the 44 weather stations that distributed around the Tianshan Mountain area,the author calculated and analyzed the precipitable water and the precipitation conversion efficiency with empirical formula about atmospheric precipitable water.The result showed that there was more precipitable water in summer than in winter in Tianshan Mountain area.From west to east and from outer to inner the precipitable water varied from much to less.The precipitation conversion efficiency was higher inside Tianshan Mountain,ranging from 100‰ to 200‰,the highest 355‰.In contrast to summer,the precipitation conversion efficiency on plains surrounding the mountain such as Yili,Shihezi etc.was higher in winter,between 80‰ and 125‰.This indicated that there was more potential to exploring atmospheric water resources.

Key words: atmospheric precipitable water, the total precipitable water, the total precipitation, precipitation conversion efficiency