In Huanshandak Sandland, China, net photosynthetic rate (P N), transpiration rate (E), stomatal conductance (g s), intercellular CO2 concentration (C i), water use efficiency (WUE), photochemical efficiency of photosystem 2 (Fv/Fm), and leaf nitrogen content were compared for Hedysarum fruticosum var. mongolicum (H.f.m.), a nitrogen fixing shrub, and Salix gordejevii (S.g.), a nitrogen non-fixing shrub. P N, E, and g s of the two shrubs were similar in trends, i.e. two peaks were observed in diurnal courses. However, except C i, other parameters of H.f.m. were higher during the measured days than those of S.g. The midday depression of P N was mainly due to decrease in stomata conductance and to reduction of Fv/Fm at midday. The higher P N of H.f.m. was consistent with the higher leaf N content and there was a positive relation between them. In addition, several C4 traits were found in H.f.m., i.e. high saturation irradiance and WUE, low dark respiration rate, and C i, which partly resulted in higher P N. This seems to indicate that the C3 plant H.f.m. may have C4 photosynthesis pathway or C4 enzymes.