Abstract: The space-for-time substitution method was used in this study, i.e. under identical or similar site conditions within a certain spatial scale, the mobile sands with different treatment years in different locations were selected to substitute for the mobile sands with different restoration years in the same growth location. In oder to clarify the effects of different vegetation restoration years on soil mechanical composition, four types of treatment were selected in the demonstration area of Ruoergai county, i.e. non-controlled alpine mobile sand dunes, the controlled sand dunes with three-, five- and ten-years of ecological restoration. The results showed that there was a significant difference in the content of soil particles between the sand dunes and the grassland soils. With the increase of treatment time, the content of fine particles such as clay and silt in the sand dunes gradually increased. And soil particles at different depths gradually improved to be finer in the surface layer than in the lower layer, which might be caused by the restoration of surface vegetation. After 10 years of sand desertification, the soil in the sand dunes had been improved to a certain extent. However, from this study, it could be seen that the soil formation process was a very slow process and the prevention was more important than vegetation restoration in the alpine regions. Therefore, we should continue to strengthen the protection and management of ecosystems in the fragile area, so as to avoid the difficult restoration of soil ecological environment caused by soil desertification.