Abstract: In order to explore the heavy metal Cd resistance of Iris tectorum., Canna indica, Thalia dealbata, Lythrum salicaria and Typha angustifolia. A pot experiment was conducted to study the effects of different concentrations of Cd on physiological and biochemical indexes of 5 wet ornamental plants. The results showed that the treatment with high concentration of cadmium, the order of cadmium accumulation in the above ground and root of 5 plants is C. indica > L. salicaria > T. angustifolia > I. tectorum > T. dealbata. With the increase of cadmium concentration, the soluble protein content of C. indica, T. angustifolia, T. angustifolia and T. dealbata showed a trend of increasing first and then decreasing, while the I. tectorum showed a slow increasing trend. The content of free proline in C. indica, I. tectorum, L. salicaria and T. angustifolia all showed an increasing trend, while the content of T. dealbata showed an increasing trend at first and then decreasing trend. Malondialdehyde content and relative conductivity of leaves of 5 ornamental plants increased with the increase of cadmium concentration. Under heavy metal Cd stress, the changes of malondialdehyde and relative conductivity in plants are in good synchronization, while the changes of soluble protein and free proline content are in poor synchronization. The ability to resist heavy metal cadmium was T. angustifolia, C. indica, I. tectorum, L. salicaria, T. dealbata.