Abstract: Due to the fragile ecological environment and the influence of human engineering activities, the loess slope geological disasters such as landslides have been increasing in Loess Plateau. The loess slope protection by vegetation is the effective means for restoration ecology and geological disaster prevention. in this paper, in order to ascertain the connection between the plant growth characteristics and the slope habitat, the engineering geological characteristic and the vegetation community structure will be studied by field investigation; and then the influence of roots on physical and mechanical parameters of soil will be analyzed by in-situ test, and the slope protection effect of plants will be clarified. On this basis, the theory and techniques of loess slope ecological protection of plants will be established. The research results can promote the engineering application of plants in loess area, and be the guidance of loess slope ecological protection technology in northwest China.