Characteristics and soil physical properties of plant communities undergoing desertification in steppes located in north central Ningxia, China were studied. The investigation was carried out to probe the responses of plant communities and changes in soil physical properties that occur during desertification of steppes. It was found that the dominant species in steppes with potential for desertification were Lespedeza potaninii, Artemisia scoparia Walds, and Pennisetum centrasiaticum. In steppes subjected to only light desertification, Pennisetum centrasiaticum and Sophora alopecuroides were dominant. The species Utricularia australis and Corispermum hyssopifolium were dominant in steppes experiencing moderate desertification. In steppes subjected to severe desertification, Agriophyllum squarrosum, Aneurolepidium dasystachys and Utricularia australis were dominant, and in steppes with extremely severe desertification Agriophyllum squarrosum was dominant. When such grasslands experienced intensifying desertification, their biomass, Shannon-Wiener index, richness index, and ground cover tended to decline. The biomass of grasslands suffering light desertification was 23% higher than that of grasslands with potential for desertification. As desertification proceeded, the soil bulk density and coarse sand content of grasslands increased but their soil moisture and clay-silt content tended to decrease most significantly. The desertification of grasslands caused the soil to form a coarse texture and thus increase its bulk weight, with the consequence that soil moisture and silt content tended to decrease. As desertification intensified, these changes made the soil more susceptible to erosion, so that, directly or indirectly, the productivity of such grasslands inevitably must decrease. Therefore, the desertification of steppes involves progressively less retention of moisture and fine soil particles, leading to desiccation and erosion of the soil, changes in plant species, and inevitable loss of productivity.