Abstract: In the process of ecological restoration of grazing exclusion desertification grassland in northest Sichuan, the variation characteristics of soil organic matter, total nitrogen and hydrolytic nitrogen in 0−40 cm soil layer of unrestored sandy land, and grazing exclusion grassland with ecological restoration time of 5 and 10 years respectively were studied. The results showed that with the increase of grazing exclusion time, the vegetation coverage and height increased significantly, and the contents of soil organic matter and total nitrogen in each soil layer increased, especially in 0−20 cm soil layer. After 10 years of grazing exclusion, the contents of soil organic matter and total nitrogen in sandy land increased by 34.05% and 27.89% respectively, which were significantly higher than those in unrestored desertification grassland. However, the content of soil hydrolytic nitrogen in each soil layer decreased at first and then increased. In 0−20 cm soil layer, the hydrolytic nitrogen content of the fenced desertification grassland with 5-year grazing exclusion decreased by 23.80% compared with that of the unrestored desertification grassland. Compared with 5-year grazing exclusion sandy grassland, the hydrolytic nitrogen increases by 24.19% in 10-year grazing exclusion sandy grassland. In the soil layer of 20−40 cm, the hydrolytic nitrogen content of sandy grassland with 5-year grazing exclusion decreased by 31.49% compared with that of the unrestored desertification grassland, and the hydrolytic nitrogen content of desertification grassland with 10-year grazing exclusion increased by 1.13% compared with that of the 5-year grazing exclusion desertification grassland.