Two forms of Casuarina equisetifolia from Yuhuan and Taizhou,Zhejiang province were selected as experimental materials,numbered Bland R5,for studying salt resistance mechanism under NaCl stress.The results showed that superoxide dismutase(SOD) activity and malondialdehyde content in B1 was higher than that in R5,while peroxidase(POD) and catalase(CAT) activity in R5 were higher than that in Bl.The experiment indicated that B1 got more content of O2-in leaves than R5,causing more hurt.Comprehensive analysis on activities of antioxidant enzymes and MDA content resulted that R5 had stronger salt tolerance than B1.