Abstract: The effect of sheep dung return presenting a certain pattern of gradient distribution in spatial was a very important factor which effected the spatial distribution of soil and vegetation and dynamics of succession in meadow with free grazing conditions. In order to develop a deeper understanding on the effect of grazing to the pattern of influencing and the mechanism of action of meadow in desert steppe. we conducted a research that the grass plant diversity and the relationship between plant diversity and soil environmental factors were studied by setting up six gradient sequence sample (1.41—1 581.68 g/m²) according to the natural surface of sheep dung quantity gradient in Ningxia desert steppe ecosystem. The results showed that plant community presented a trend which the dominance status of Penniseluru cenlrasialicuru was substituted by Sophora alopecuroides: the importance value of cenlrasialicuru decreased from 2.07 to 0.19, the importance value of alopecuroides increased from 0 to 1.25. The plant diversity index of margalef increased from 0.64 to 2.26, Shannon-Wiener increased from 0.35 to 1.86 respectively but the index of Pielou was not necessarily change rule with the increase of grazing intensity. The main soil environment factors affecting the plant diversity were soil total nitrogen as the significant one, moisture content and available nitrogen at 0-5 cm soil layer, soil organic carbon and nitrogen as the significant one at 5—10 cm soil layer respectively. Preliminary research conclusions considered the one most important factor affecting the plant diversity was the increasing of soil nitrogen and this result may be related to nutrient return of grazing livestock excreta. Confirming where the nitrogen comes from and goes to may be the primary mission in further recognizing of the mechanism of action about sheep dung return in the grassland ecosystems of desert steppe.