Wind-sand disaster is severely threatening the normal function of oasis farmland in Ulan Buh Desert. Forms, characteristics, spatio-temporal variation of wind-sand disaster threatening oasis farmland were investigated with methods of field observation and laboratory experiment. The results show that shiftingsand intrusion and wind erosion are the main forms of sand disasters, and sand source mostly comes from eroded soil, sporadic shifting sand dune inside oasis, sand movement and sand flowing activity outside oasis.Wind-sand disaster has the characteristics of generality, seasonality, anisotropy, cumulative effect and diversity etc. Soil wind erosion in oasis farmland decreases from the oasis edge to the core, and depth and intensity of soil wind erosion decreases too. In the same forest network, erosion depth and intensity increase from the edge to the core of farmland. Sand matter deposits near the shelter belt edge and field ridge, and soil erosion happens in the other areas. Erosion depth and intensity are larger in sandy farmland than that in clay farmland. Wind erosion is weaker in autumn but stronger in spring.