Located in the hinterland of the Tibetan Plateau in China, the Three-River-Source Region is known as "Chinese Water Tower".The distributions and variations of precipitation and cloud water resources over this region are fundamental to the fresh water resources in China, and also affect the ecosystems of the Three-River-Source Region and the downstream area.This paper reviews and summarizes the research results on the spatial distribution and temporal evolution characteristics of precipitation and cloud water resources in recent decades, the impact mechanism of precipitation, and the prediction of future precipitation trends over the Three-River-Source Region, and gives the prospects for further research.