Abstract: Taking the plateau wetland Dianchi Lake and the Napahai Lakeside zone as the research site, the lakeside with the dominant species of Scirpus Validus as the research object, and detected the morphological, specific leaf weight and the photosynthetic properties of the species to compare and analyzed the differences in these parameters under different altitudes. The results show that compared to Dianchi wetlands, S. Validus plants in Napahai wetlands are small in height, and have low specific leaf weight and photosynthetic capacity. In Dianchi and Napahai wetlands, the leaf length of S. Validus are 205.6 and 116.5 cm, the basal diameter are 10.94 and 8.77 mm, and the specific leaf weight are 229.85 and 107.77 g/m², respectively. The net photosynthetic rate of S. Validus in Dianchi and Napahai wetlands are 19.43 and 12.36 μmol/(m²·s), respectively. The stomatal conductance of the species in the 2 sites were 0.63 and 0.30 mol/(m²·s), and the transpiration rates are 3.43 and 2.34 mmol/(m²·s), respectively. These results indicates that the morphological size and the productivity of S. Validus have different appearance in growing sites with different altitudes. The harsh growing conditions at the higher altitudes should be important reasons for plants with small size and low productivity. Our study provides a case study on how wetland plants adapt to environmental changes from plant functional trait properties.