Sandy alpine grasslands are an important community type in source regions of the Yangtse and Yellow rivers, which affect the progress and reversal of desertification. Our objective was to determine sandy alpine grassland characteristics and the relationship between plant distribution and microtopography. Typical sandy alpine grassland distributed in hilly sloped lands, floodplains, foothills, and gully areas were selected as four sampling locations and sampled using four sampling lines for a total of 60 samples. Analyses were performed by using winTwin 2.3, Canoco 5.0, and Excel 2013 software. The species composition of the investigated community was simple, with 29 species grouped into 27 genera and 16 families. The occurrence of Leymus secalinus, Heteropappus altaicus, and Corispermum declinatum indicated that desertification of alpine grassland is in progress, and the vegetation community was successional to the direction of xeric. Species standard frequency distribution varied with different microtopography, the proportion of dominant species was generally lower than that of rare species, and the vegetation community was in a highly successional stage. We identified seven associations through TWINSPAN:AssⅠ. L. secalinus+H. altaicus+Saussurea woodiana, AssⅡ. L. secalinus+Kobresia royleana + C. declinatum, AssⅢ. L. secalinus+Elymus dahuricus+Ajania tenuifolia, AssⅣ. L. secalinus+Thermopsis alpine, AssⅤ. E. sibiricus+Poa annua, AssⅥ. Elymus sibiricus+E. dahuricus, AssⅦ. C. declinatum. The distribution of the seven associations in the DCA ordination graph showed certain regularity. The results of the CCA ordination reflected that slope and aspect are the dominant factors among microtopography in the species distribution of sandy alpine grassland.