Abstract: In order to approach improvement ways of deteriorated grassland on Qinghai-Tibet Plateau, in this paper, the quadrant survey method was used to study the dominant species and photosynthetic characteristics of alpine meadow in Maqu county, Gansu province. The feature index and vegetation cover degree were also analyzed by mean of the grey correlative degree. Results showed that Stipa aliena, Bupleurum chinense, Saussurea nigrescens, Poacrymophila keng and Anemone revelries were main dominant species in this area. The grey correlative degree between the population feature and vegetation cover degree: aboveground biomass>height>density. The grey correlative degree between photosynthetic character index and vegetation cover degree: intercellular CO2 concentration> transpiration rate> net photosynthetic rate> stomatal conductance. The formation of dominant populations depends on the capability to exchange gases between individual plant and outside. To improve the alpine meadow productivity, we should cultivate dominant species basing on the maintenance of biodiversity.