Pot experiments were carried out to investigate the effect of straw addition on biomass, contents of malonyldialdehyde (MDA), activities of superoxide dismutase (SOD), catalase (CAT), peroxide enzyme (POD) and the accumulation of heavy metals (Pb, Zn, Cd) in Ricinus communis under the stress of Pb/Zn mine tailing. The results indicated that straw addition significantly increased fresh weight, height and root length of Ricinus communis. The contents of MDA and the activities of SOD, POD, CAT in the leaves of Ricinus communis under the straw treatments were 48.08%, 7.28%, 28.60% and 4.74% lower than the control, respectively. DTPA-extractable contents of Pb, Zn and Cd in the Pb/Zn mine tailing decreased significantly. The contents of Pb, Zn and Cd in plant organs of Ricinus communis decreased significantly with straw addition. An extremely significant positive correlation were observed between the activities of POD, SOD and the contents of Pb, Zn and Cd in the leaves of Ricinus communis, and significant or extremely significant positive correlation were observed between the contents of Pb, Zn and Cd in plant organs of Ricinus communis and DTPA-extractable contents of Pb, Zn and Cd in Pb/Zn mine tailing.