Forest vegetation has various service functions,such as climate regulation,soil conservation,and nutrients accumulation,species conservation and water conservation.One of the most intuitive functions of forest vegetation was water conservation.Studies showed that various types of forest vegetation differed in their ability of water conservation.It has been receiving more attention due to the worsening global water environment and increasing human demand on water.Remote sensing images and meteorological data make it possible to accurately measure annual precipitation and evaporation of forest ecological system with the rapid development of geographic information system technology.All of these make the water balance method with a higher credibility than other methods to estimate physical quantity of forest water conservation.Three kinds of typical forest vegetation in Yunnan Plateau were selected as the research objects.By using the principle of water balance to study canopy interception,litter and soil water storage capacity of three kinds of forest vegetation.The results showed that the soil water storage was the main way of forest water conservation functions.According to the canopy intercept quantity and capture rate metrics about various of vegetation,the order of canopy intercepting water capacity is as follows:Pinus densata(20 9.87 t/hm~2,28.87%)> Betula platyphylla Suk.(194.17 t/hm~2,19.82%)> Quercus aquifolioides(111.78 t/hm~2,16.32%)Litter water-holding capacity included two aspects:maximizing water holding capacity and the water holdup.The order of maximum water holding capacity on litter is as follows:Pinus densata(35.79 t/hm~2)>Betula platyphylla Suk.(24.52 t/hm~2)>Quercus aquifolioides (18.49 t/hm~2).The order of water holdup on litter was Quercus aquifolioides(177.42%)>Betula platyphylla Suk.(152.08%)>Pinus densata(138.48%).The order of soil water storage capacity was Quercus aquifolioides(673.19 t/hm~2/a)>Pinus densata(610 t/hm~2/a)>Betula platyphylla Suk.(549.84 t/ hm~2/a).The order of water conservation capacity is as follows:Pinus densata(855.66 t/hm~2)>Quercus aquifolioides(803.46 t/hm~2)>Betula platyphylla Suk.(768.53 t/hm~2)in the same forest per unit area.The study on water conservation functions of typical forest vegetation in Yunnan plateau not only provides the guidance basis for the local forest management and production,but also ensure the water security of nature reserve and even in Yunnan Province.It is of very important significance under the background of climate change.Study forms the foundation to benefit accounting and management of forest ecological in the future.In addition,the research has scientific guiding significance for strategy adapt to climate change.