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In order to provide technical basis for prevention of desertification grassland in agro-pastoral ecotone in Siziwang banner, Inner Mongolia, the in-situ test was adopted to study the blown sand movement laws and explore the mechanism and protection effect of soil wind erosion for degraded grassland with 20% coverage, repaired grassland with 40% coverage of Caragana korshinskili gapped belt scheme plantation and 60% coverage of Agropyron mongolicum randomly distributed plantation, the movable wind erosion tunnel and its supplement equipment were used. The results indicated that, at the same wind speed in the wind tunel, the descending order of soil surface roughness was C. korshinskili grassland, A. mongolicum grassland and degraded grassland. The average roughness of C. korshinskili grassland was 2.46cm, which was 1.95 times of A. mongolicum grassland and 2.76 times of degraded grassland. With the decrease of height from the ground, all the wind speeds of three grasslands were decreased, and when wind speed was 9m/s in wind tunnel, wind velocities at height of 8cm were reduced by 82.23%, 66.67% and 61.11% for C. korshinskili grassland, A. mongolicum grassland and degraded grassland compared with those at height of 64cm, respectively. The sand transport rate of C. korshinskili grassland was the smallest, and the sand transport rate curves of A. mongolicum grassland and degraded grassland were decayed in the form of exponential function along with the increase of height from ground, and the curve of degraded grassland was decayed faster. Whereas, the sand transport rate curve of C. korshinskili grassland had a maximum value at its top of 30cm, and it was exponentially decayed under its top. Therefore, the C. korshinskili grassland had significant effects on obstructing and changing wind-sand flow, and it could still achieve good anti-erosion effect at low vegetation coverage.