The classic species diversity-ecosystem function relationship studies attached more importance on single function and its correlation with diversity despite the fact that most ecosystems are managed or valued for their ability to maintain multiple goods and services simultaneously, so called multifunctionality. Therefore, multifunctionality is an important perspective for biodiversity-function research in point of view of comprehensive function analysis. We conducted an ecosystem multifunctionality vs. biodiversity study on the Tibetan Changtang Plateau, in terms of seven indicators of ecosystem functioning related to plant growth (aboveground biomass, belowground biomass), nutrient cycling (soil total nitrogen content, soil NO₃^- and NH₄⁺ content, soil phosphorus content), and soil carbon storage (soil organic carbon density). Z scores (standardized deviates) of the seven indicators were assessed to represent multifunctionality. The multifunctionality index (M) was calculated as the average Z-score for all indicators measured in each site. Linear regression was used to analyze the relationship between multifunctionality and species diversity indices (Species richness, Shannon-wiener index, Simpson dominance index, Pielou evenness index). We also tested whether ecosystem multifunctionality and species diversity were associated with climatic factors (mean annual temperature and mean annual precipitation) by using linear regression. It was indicated that ecosystem multifunctionality indices were correlated most significantly with species richness, notable positive with Shannon-wiener and Simpson index, but not with Pielou evenness index. Separate analyses of functions related to the plant growth, soil carbon storage and nutrient cycling also yield significantly positive relationships with species richness. Precipitation plays a positive role in affecting species diversity and ecosystem multifunctionality indices, as the species diversity and multiple functions increase linearly with mean annual precipitation. The present study highlights the importance of species richness in maintaining multiple ecosystem functions, goods and services in Changtang Plateau. Because each species contribute to different functions, studies with focus on single function (i.e. net production) might underestimate levels of species richness required to maintain multiple ecosystem goods and services. The alpine grassland ecosystem is vulnerable to climate change and human induced biodiversity loss. It is therefore implied that species loss may cause severe consequence for ecosystem functioning, which would threaten ecosystem health and human well-being in this region. We suggest that the species richness of native species must be maintained and sustained in order to meet the goal of degraded grassland restoration and sustainable management on the Changtang Plateau.