To investigate the alleviated effects of Cd stress on rice roots with Pr treatment, solution culture experiments were conducted to study the effects of different Pr levels (10, 20, 40, 60, 80, 100 mg/L) on root physiological characteristics of rice (Oryza sativa L.) under Cd stress. The results showed that Cd stress had significant inhibitory effects on root growth. Under Cd stress, the root dry mass, root activities, SOD, APX and CAT activities decreased by 31.6%, 46.1%, 23.3%, 57.6% and 40.1%. However, POD activities, electrolytic leakage, MDA and proline content were significantly higher than those of control, which were 1.61, 2.05, 1.82, 1.63 times respectively. With the treatment of 10~80 mg/L Pr, root growth was reconditioned to different degrees and the damage of Cd toxicity reduced. It proved, by the experiment, that Pr can improve root activities and proline content, reduce cell membrane permeability and MDA content, and keep the activities of SOD, APX and CAT of rice root. By contrast, the optimum concentration of Pr was 40 mg/L. However, under the treatment of 100 mg/L Pr, the toxic effect of C was aggravated.