Abstract: Except one or two period, the quantitiy of oxygen radical and the activities of superoxide dismatase and ascorbic acid peroxidase in the leaves, stems and roots of trans-BSFE gene and its signal peptide and propeptide sequence tobacco were all higher than those of the common tobacco. We infer the change of the quantity of oxygen radical relates with the hydrolyzing activity of BSFE protein, and the change of activities of superoxide dismutase and ascorbic acid hydrogen peroxidase ralate with counter-adaptation to the expression of exogenons BSFE gene and its product accumulation of the transgenic tobacco.