The flow fields, protective efficiency of sand-blocking fences are simulated in wind tunnel experiment, and the erosion or accumulation phenomena of fences along the Qinghai-Tibet Railway in the section of Tuotuohe River region are observed in situ. There exists blocked-rising, collected-accelerating, decreased-depositing and diffused-restoring regions when airflow traverses sand-blocking fences. Two decreased-restoring regions as well as two accelerating regions present behind the fences. The decreased-restoring regions happen at the height of 3 cm and 20 cm above the earth surface, and the two accelerating regions happen within near surface and at the height of 35 cm above the earth surface, respectively. As the inlet wind speed increases, the wind accelerating range before fences approaches the fences and the starting point of wind\|restoring region departs away fences. Wind speed abruptly decreases just after fences, which leads sand grains to deposit in this region. Sand-blocking mass and sand transport after fences increase exponentially with wind speed. Fence exerts distinct effect with sand-blocking ratio of over 80% along Qinghai-Tibet Railway. Sand-blocking ratio decreases linearly with wind speed. Wind erosion occurs on the southwest area of sand-blocking fence in the section of Tuotuohe River region, with the most wind-erosion depth of 16.7 cm, and it represents sand burial over the other areas and the most sand-accumulation depth is 19.9 cm.