Abstract: Thecontents of soluble proteins and chlorophyll of the detached leaves of rice treated bytriadimefon(mass concentration=20 mg/L) increased. The results indicated that triadimefonretarded the senescence of rice leaves. During the senescence of detached rice leaves,both the activities of superoxide dismutase and catalase and the contents of ascorbic acidand reduced gluthione decreased, which was inhibited by triadimefon. These resultssuggested that triadimefon enhanced the protective ability against enhanced lipidperoxidation.