OBJECTIVE: To investigate the eliminating ability of catechin to eliminate O2-* and *OH. METHODS: The ability of catechin to clear away O2-* and *OH was respectively measured by faintness chemiluminescence and spin trapping assay. RESULTS: IC50 that catechin eliminated O2-* and *OH was 6.16, 0.59 g/mL respectively, and the eliminating ability of catechin was much stronger than that of the extract from liquorice, rosemary, grape pip, giant knotweed and ginkgo leaf. CONCLUSION: Compared with several important natural plants of antioxidants, the eliminating ability of cathechin is the best.