Vegetation construction in a serious water loss and soil erosion area—— — Wufendigou small catchment has been performed for more than20years.The various plant communities of high-forest,shrub-forest and grassland are mosaically distributed over the small catchment.Its cover ratio of the vegetation to the area has come up to80%.Such vegetation construction has efficiently controlled water loss and soil erosion,but a quite amount of water resource has also been consumed,which is called ecological use of water(EUW).During the growing season of the year2002,evapotranspiration of the various vegetations,water storage capacity of the various soil types and precipitation etc.were measured in the small catchment.Then EUW of the four vegetation types was calculated as:①agricultural field,5321.3m³ /hm² ;②the high-forest,4654.8m³ /hm² ;③the shrub-forest,4047.8m³ /hm² ;and④the grass-land,3244.3m³ /hm² .While,EUW amount of different components in the catchment was esti-mated as follows:①EUW amount of all the vegetations,1500000m³ ;②the reservoir marsh,260000m³ ;and③the villages,4000m³ .Thus,the total EUW amount of the whole catchment was1700000m³ .It is noticeable that EUW amount of all the vegetations and the whole catchment exceeded precipitation about 200000and400000m³ in the same period respectively.This figure means that soil water storage capacity of the catchment would be consumed20～30mm.Therefore,con-struction of appropriate vegetation pattern and control of EUW amount would have very impor-tant role for maintaining stability of ecosystem and improving eco-environment.