We studied the effects of manganese stress on Arundo donax. The Hoagland nutrient solution served Mn provider agent by treating seedlings with final Mn concentrations of 0.0(control group), 0.2, 0.6, 1.0, 1.4 mmol/L. The physiological and biochemical components of giant reed leaves were measured at 8, 16, 24, 32 d after Mn treatment, and photosynthetic characteristics of giant reed leaves were measured at 47, 94 d after Mn treatment to explore its tolerance to manganese. The results showed that no significant changes were detected in the chlorophyll content among the treatments and the control except for the case of 0.2 mmol/L at 24 d. The content of proline was significantly higher than that of the control in the early stage (8 d), then decreased(16 d), and was the lowest at 32 d, with no significant differences among the treatments and control in the latter three stages except for the datum of 1.4 mmol/L at 24 d. No significant differences were observed in the MDA content except for the case of 0.6 mmol/L at 24 d. Though no differences were displayed in the relative exosmosis rate among the groups in the former stages of the treatment, the values increased significantly at 32 d when compared with the control except for that of 0.6 mmol/L treatment. Compared with the control, the activities of SOD were inhibited significantly and the activities of CAT were enhanced under 1.4 mmol/L Mn in the latter two stages. However, Mn treatment imposed little influence on the activity of POD through the experimental duration except for distinct inhibition at 16 d. Both the values of net photosynthetic rate tested at 47, 94 d decreased obviously with the increase of Mn concentration, till the lowest 6.5 μmol/(m2?s). The seedlings presented no symptoms of manganese toxicity during 96 d, indicating giant reed had certain ability of tolerance to Mn stress, which made it possible to be considered as a potential crop for ecological restoration of manganese ore wastelands.