A pot experiment was carried out to investigate the effects of three organic amendments (organic carbon material, rapeseed cake and pig manure) on antioxidant enzyme activities in roots, flag leaves and heavy metal uptakes of a low grain Cd accumulation rice cultivar at a heavy metal mixed contaminated paddy soil. The results showed that at initial stage of panicle emerging, application of higher rate mixed organic carbon material inhibited the growth of rice, and reduced antioxidant enzymes activities of rice roots. Application of rapeseed cake and pig manure significantly increased the biomass, and decreased Zn and Cd concentration in roots and straws. Application of rapeseed cake increased antioxidant enzyme activities of rice, and pig manure resulted in premature senility from initial stage of panicle emerging. As compared with the control, application of rapeseed cake increased biomass by 14.0% - 49.2%, decreased melondialdehyde (MDA) content by 15.6% - 31.3% and 15.3% - 51.8% in roots and flag leaves, increased catalase (CAT) activity by 40.9% - 79.8% and 9.0% - 143.8%, respectively. Concentrations of Zn in roots and straws decreased 19.1% - 26.4% and 10.1% - 26.1%, Cd decreased 32.7% - 58.8% and 16.8 - 62.1%, respectively. Application of pig manure increased biomass by 10.8% - 16.7%, increased MDA content by 53.1% - 59.4% and 18.5% - 44.9% in roots and flag leaves. Concentrations of Zn in roots and straws decreased 29.7% - 42.6% and 15.2% - 52.9%, Cd decreased 22.5% - 44.0% and 12.1% - 64.5%, respectively.