Abstract: Leaf anatomical structure, photosynthetic enzyme activity, glycollate oxidase activity and stable carbon isotopic composition (δ13C) in leaves from different habitat reed distributed over the Hexi corridor of Gansu province were comparatively investigated. The results indicate that the bundle sheath cells of swamp reed do not contain chloroplasts, the ratio of RUBPcase activity/PEP case activity, activity of glycollate oxidase and δ13C value in leaves of swamp reed fall in ranges typical for C3 photosynthetic plant (wheat). The typical Kranz structure and the bundle sheath cells containning dimorphological chloroplasts were observed in leaves from sand dune reed, the ratio of RUBPcase activity/PEPcase activity, activity of glycollate oxidase and δ13C value are quite similar to that of typical C4 photosynthetic plant(Maize). Salt meadow reed and salt-meadow-sand-dune reed compared with swamp, although there are Kranz structure and bundle sheath cells containning chloroplasts in the former leaves, and the ratio of RUBPcase activity/PEPcase activity in the former leaves are lower than in the latter leaves, activity of glycollate oxidase, especially δ13C values in the former leaves are similar to that of the latter leaves. These results may suggest that, in the Hexi corridor of Gansu province, environmental factors induce an active evolution of the pathway of photosynthetic carbon metabolism within reed species.