Vegetation measure is one of the most useful and basic methods to harness the typical soil and water loss area of Gua ngdong province. As a case in Shima small watershed, the benefits of different plants on reduction of water and sediment yield were compared. The result showed that the plant colonies of different type and stucture brought different benefits. The influence of rain to the different reduction benefits was also analysed. The synthetical benefits of soil and water conservation after harness in Shima small watershed are evaluated.