Abstract: For 364 field sites representing seven grassland types in Xinjiang, species lists were compiled, and the distribution of plant families, genera and species across the different grassland types cataloged. In addition, we examined the species richness (SR) response to mean annual precipitation (MAP), mean annual temperature (MAT) and altitude. The Poaceae and Ateraceae were the dominant families, and Stipa, and Seriphidium were among the dominant genera at all sites. The grassland types ranked for SR (from high to low): temperate meadow steppe (7.73), temperate steppe (5.04), alpine steppe (4.36), temperate desert steppe (3.99), temperate steppe desert (3.02), temperate desert (2.08), low plain meadow (1.43). Patterns of SR response to MAP, MAT and altitude were also detected. In Xinjiang grassland temperate steppe, SR was positively and linearly related to MAP, but unimodally related to MAT and altitude. In alpine steppe and low plain meadow, SR was positively and linearly related with MAP and negatively related with MAT, but SR decreased from low to mid altitude and then increased with increasing altitude. In temperate desert steppe, SR was significantly positively related to MAP, but was not significantly related to MAT and altitude. In alpine steppe and low plain meadow, the SR was positively and linearly related to MAP and negatively related to MAT, but unimodally related to altitude. No significant relationship was found between SR and MAT, MAP, or altitude in temperate meadow steppe and temperate steppe desert grasslands. The above results in the different grassland types might be explained by response characteristics of particular species, spatial variation of temperature and precipitation, and the altitude range, steepness of slope and large scale climate characteristics of the study area.