Abstract:Relationship between biodiversity and productivity has become a central issue in ecological research because the world is facing the problems of biodiversity losing and ecosystem degradation. However, the relationship between biodiversity and productivity and the underlying mechanism are not clear yet especially when we consider the environmental and anthropogenic impacts. To discuss the relationship between biodiversity and productivity in different intensities and types of anthropogenic activity, a study of two peak growing seasons in the Hulunbeir grassland was carried out. The relationships between species richness and above-ground biomass according to six plant functional groups in three different grassland-use types were discussed. Results indicated that: (1) Grassland biodiversity and productivity varied significantly with different grassland-use types. Biodiversity had the decreasing trend from grassland mowing (Mw) to explosure (Ex) and grazing (Gz). The Shannon-wiener index, Simpson index and species richness were all significantly different among the three grassland-use types. The Mw had the highest, the Ex had the medium, and the Gz had the lowest above-ground biomass. (2) Grassland plants were classified into six plant functional groups. The annuals and biennials (AB) were the dominant functional group in Gz and the above-ground biomass of AB had no obvious relationship with species richness; perennial rhizome (PR) grass, perennial bunchgrass (PB) and perennial forbs (PF) played important roles in Mw. The above-ground biomass of PR grass and PB reduced with the increase of species richness while the above-ground biomass of PF did not varied with species richness; PR grass and PB were the dominant plant functional groups in Ex. The rest functional groups (LG, SS, AB, PF) had a weak spatial heterogeneity with the similar levels of frequency, abundance and biomass. (3) There was a positive linear relationship between species richness and above-ground biomass in Ex. No significant relationships between species richness and above-ground biomass were found in Gz or Mw.