Abstract: Light use efficiency is an important indicator of plant photosynthesis, and also is crucial for improving ecosystem productivity. In this study, we selected Zoige Plateau, an ecologically sensitive alpine area, to evaluate the light use efficiency of the dominant plant species in two typical ecosystems, namely alpine meadows and wetlands, and to analyze the impacts of environmental factors on light use efficiency in each ecosystem. The net photosynthetic rate and light use efficiency of Elymus nutans dominated in alpine meadows were higher than those of Carex muliensis dominated in alpine wetlands, but the difference was not significant. Regarding Potentilla anserina, a common species in both ecosystems, the net photosynthetic rate and light use efficiency were higher in alpine wetlands than in alpine meadows. Regression analyses revealed that there were highly significant correlations between the light use efficiency of the two dominant plant species (E. nutans and  C. muliensis) and microclimatic and edaphic factors. In contrast, the light use efficiency of the common plant species P. anserina was mainly affected by microclimatic factors only. This study indicated that the light use efficiency varied with alpine plant species. For the dominant species, the light use efficiency was mainly influenced by microclimatic factors, especially air temperature, which was the most important factor affecting the light use efficiency of alpine plants.