Abstract: Due to alternative occurrence of floods and droughts as well as the influence of neo-tectonic movement, the channels of rivers in Horqin Sandy Land change frequently. In dry seasons, a large amount of sand-dunnes formed from various deposit bodies of loose sand under strong winds. Further, these sanddunes exert significant effects on the channels of rivers in flood period. When the channels change or have a big leap, formed sand-dunes would move and change their shapes under prevalent wind and groups of sand-dunes form by mutual linkage. After a long development period, a large stretch of sandy land emerges. Meanwhile,in the process of transverse swing, river can destroy some formed dunes through gradation. However, the land surface process in the region is mainly the formation of sand-dune groups because of the hindrance of sand-dune group itself, active vegetation action and non-evenness of river change. Accordingly, the river changed its way does the same work in the new channel. The effects of river is changeable with the Positions such as concave and convex beaches, upper or lower reaches, and the corresponding relations to the wind direction i. e. windward and leeward, perpendicular or oblique as well as parallel. In this region, sand-dune groups, lakes and marshes, meadows and pitches of steppe distribute interlacingly and at intervals,and sand-dune zones arrange in line along the beaches of present and ancient channels. Also, aeolian sand limnological facies, riverine factes change alternatively and further transit mutually in Quaternary strata. Therefore, river evolution has very vital initiative and promoting effects on the formation and development of sand——dune groups and sandy land in natural conditions.

Key words: Horqin Sandy Land, river evolution, loose sand deposit body, riverine landform, Quaternary strata