The field investigation to megadunes in the Shashangou section of Dunhuang-Golmud Railway disclosed that the megadunes are not composite Megadunes, but drift sand covered on denuded hills and platforms which are caused by the uplifting of the alluvial-pluvial fan ahead of Altyn Tagh Mountains. The subsurface terrains are steady, so the megadunes in the Shashangou will not move as a whole, thus its threat to the Dunhuang-Golmud Railway is negligible. The meteorological data are interpreted to calculate the maximum possible sand transport quantity and the maximum possible sand transporting direction. Results show that the sand transporting direction is parallel to the railway, and the wind brought by the micro-terrain can reduce the sand hazards. The possible aeolian-sand hazards are separately investigated. From the results, the authors believe that the intensity of the aeolian-sand hazards in this area can be controlled, and consequently, it is safe for the railway to be built across the valley. Detailed suggestions are provided both qualitatively and quantitatively for setting up an effective sand controlling system.