Abstract: In order to explore the characteristics of sediment in the Badain Jaran Desert,the grain size characteristics and micro-morphololgy characteristics of the surface of the desert surface were studied by field collection and experimental analysis.The results show that:(1)On the whole,the marginal area of the Badain Jaran Desert is dominated by fine sand,the middle sand and the very fine sand are the second.From the local perspective,the southeast is dominated by the middle sand,and the northern part mainly consists of powdery sand.The western region is dominated by coarse sand and extremely coarse sand,which is consistent with the sorting effect of the dominant wind direction (W and NW).(2) In the north and south,the average particle size of rivers and mountains was small,and there was no significant difference in the rest areas.Sorting is best in the southeast.The relation of grain size parameters in the study area shows that σ_I is better in the southern region as M_z becomes larger,but there is no obvious rule in the region.The SK value becomes smaller as σ_I becomes smaller,and the K_g value becomes smaller as σ_I becomes smaller.(3) The quartz sand morphology is mostly long and round.The roundness of the whole is moderate,with the northwest grinding to the best,the southwest and the south the least rounded.The surface feature marks are mainly in the form of mechanical sedimentation under the environment of arid wind,and a large number of siliceous spheres and siliceous scales are present in the northwest and southeast of desert.

Key words: Badain Jaran Desert, sediment, grain size, micro-morphololgy, spatial variation