Aims Resource-use differentiation among species, which can reduce species competition for the same resources, is the main mechanism to maintain species diversity. Changes in soil temperature and moisture conditions, in the context of global change, may affect nitrogen (N) nutrition of plants of alpine meadow ecosystems. Our objective is to compare the characteristics of N uptake and resource allocation of dominant species of alpine meadow with changes in soil N and water. Methods An alpine meadow was treated with N and water addition for three years using the method of ~(15)N isotope injection. We determined the growth responses of dominant species to the N and water additions, as well as the features of N uptake capacity, N allocation and root to shoot ratio. Important findings The species showed significantly different responses to the N and water treatments, with respect to functional traits of species in N absorption capacity, root N content and root to shoot ratio. There was no significant relationship between N absorption capacity and root N content, whereas N absorption capacity was negatively correlated with root to shoot ratio across all plant species. These results indicated there was ecological niche differentiation in N uptake and a trade-off between the N absorption capacity and resource allocation strategies among species.