Taxus chinensis var. mairei was used as test material, exogenous nitric oxide (NO) fumigation treatment with different concentration (0, 0.01, 0.1, 0.5 or 1 mM) of sodium nitrop russide (SNP), a donor for exogenous NO, was used to study the effects of NO on the active oxygen metabolism index of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), Hydrogen peroxide (H2O2) and malondialdehyde (MDA) in Taxus chinensis var. mairei. The results showed that low concentration of exogenous NO treatment increased the activities of the protective enzyme, such as SOD, CAT, POD and APX of Taxus chinensis var. mairei leaves, reduced the content of H2O2, and inhibit the increase of MDA in the first three days. NO fumigation treatment enhanced the antioxidant ability of Taxus chinensis var. mairei, prevented lipid membrane peroxidation.