Traversing from Inner Mongolia to QinghaiTibet Plateau, China Grassland Transect (CGT) spans large climate gradients with main grassland types distributed. Elucidating the variation of N and P contents of different plant functional groups in terms of climatic factors (precipitation and temperature) is important to reveal the mechanisms of plant N and P contents in response to climate change. In this study, we divided CGT into two parts: the QinghaiTibet Plateau alpine region and the Inner Mongolia steppe region, then measured the nitrogen (N) and phosphorus (P) contents for 329 leaf samples collected at 132 sites along CGT. Based on the ecological stoichiometry theory, we aimed to explore the spatial patterns of N and P contents for different plant functional groups (legumes, grasses, sedges and forbs) in relation to the climatic factors. The results showed that, (1) the N and P contents of plants in QinghaiTibet Plateau alpine region were significantly higher than those in Inner Mongolia steppe region; (2) among different functional groups, legumes had the highest N and P contents and grasses had the lowest N and P contents; (3) in general, N and P contents of sedges and forbs significantly varied with mean annual precipitation and mean annual temperature. Our results also indicated that composition of plant community could affect the patterns of plant N∶P at community level. The correlations between N and P contents and climatic factors varied among plant functional groups, and forbs and sedges contributed mostly to the spatial pattern of communitylevel N and P contents with the changes in precipitation and temperature across the grassland transect.