Abstract: Based on the experiment and observation,it is clear that the biological managemental tecniques expect good results in Yanchi semi-desert area,Ningxia Hui Autonomous Region.Establishing wind break and sand fixed forest on suitable habits with shrub species of Caragana intermedia,Caragana korshinskii,Hedysarum scoparium Fisch,Hedysarum laeve B.fedtsch.,Atrapharxis bracteata A.Los,etc.is an effective method of control land desertification.The shrubery will take shape of forest and the shifting dunes will be fixed in 3~4 years.The vegetation under the shrubery will evolve to a structure predominated by improved species.In addition,there will be considerable economic benefit under reasonable development.

Key words: Semi-desert area, Land desertification, Selection of tree species, Soil moisture dynamics, Regime of sand dune moving