Conserving soil and water with grasses in the lead and in combinaton of trees with shrubs is an effective measure of grasses combined with trees practised in controlling soil and water erosion in the upper reaches of the Hanjiang River and the Beijiang River for five years in Cuangd-ong Province, Grass plants with more foliages grow with more branches and craw over the ground, which can effectively prevent splash erosion，disperse, slow down, check and reduce surface runoff, improve soil permeability and reduce soil erodibility, What's more, the principle of "gaining success by quickness" and "regaining success by superiority" must be well grasped, and attention should be paid to the cultivation techniques and fertilizer application.