Based on in situ investigation，observation，and test

green plant

slope soil physical and chemical properties

and plant community composition on the Huangling --Yan'an Highway are studied. Through analyses

plant species in the central reserve

platform and slope

and the advanced allocation model are summarized and the reasons of soil nutrient pool and improving measures are analyzed. Accordingly，several relevant conclusions are made. Soil fertility and plant restoration is complement and soil fertility is gradually restored with time after artificial vegetation construction. The number and proportion of species have a great change with the passage of time

which is beneficial to plant community of slope to reach structural stability.