By field measurement and wind tunnel simulation on sand-drift of Gobi, this paper draws the following conclusions: ① The wind-drift structure of Gobi has the feature which is different from that of mobile sand. The roughness of Gobi surface increases with wind velocity. With height increasing, the sand transport rate of Gobi surface takes on unique effect of elephant nose, that is, the sand transport rate comes to a maximum value in certain height and this height increasing with wind velocity. ② The elephant nose effect leads to the characteristic value of sand-drift in Gobi (λ)being more than 1 at all times. This indicates that the Gobi sand-drift is belonging to the unsaturated and non-accumulating state, however how great the wind velocity is. ③ The elephant nose effect of Gobi sand-drift can also answer the question why the Mogao Grottoes can not be buried by sands during more than 1000 years. ④ Therefore, in the practice of protecting sand damages, we can use gravels to cover mobile sand surface to form an underlying surface like Gobi, and making sands pass over it freely. 