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Gas exchange, photochemical efficiency, and leaf water potential (Ψ l ) of Salix matsudana (non-indigenous species), S. microstachya and S. gordejevii (indigenous species) were studied in Hunshandak Sandland, China. Ψ l of all the three species decreased from 06:00 to 12:00, and increased afterwards. S. matsudana showed higher values of Ψ l than others. Net photosynthetic rate (P N ) and stomatal conductance (g s ) of S. matsudana were the lowest among all, with the maximum P N at 10:00 being 75 % of that of S. gordejevii. Compared with the indigenous species, the non-indigenous S. matsudana had also lower transpiration rate (E) and water use efficiency (WUE). The values of F v /F m in all the species were lower from 06:00 to 14:00 than those after 14:00, indicating an obvious depression in photochemical efficiency of photosystem 2 in both non-indigenous and native species. However, it was much more depressed in S. matsudana, the non-indigenous tree. P N was positively correlated to g s and negatively related to Ψ l . The relationship between g s and vapour pressure difference (VPD) was exponential, while negative linear correlation was found between g s and Ψ l .