Abstract: The paper reports the effects of low energy Carbon and Nitrogen ion (75×10¹⁴keV/cm² )implantation into S. rebaudiana seeds.on germinant rate, relative growth weight and peroxidase of S. rebaudiana. The results showed: (1)The seed germinant rates were lower and seeding servival rates and deve lopment speeds were slower in the treated groups than those in the control in the initial period of seed germinating;but in the late period of seed germinating the relative growth weight and peroxidase activity were higher in treated groups than those in the control.(2)When seedings were transplanted into experimental field the growth and development were speeded up in treated groups than that in the control.The rate of flower bud plants were higher in treated groups than that in the control. (3)The isozymogram of peroxidase by PAGEshowed that there were 12 plants which had 1～6 basic bands and 20 plants which had B1,B2 bands in the control,but only there were 5 plants and 11 plants, respectively, in C⁺ treated groups,and there were 5 plants and 6 plants, respectively, in N⁺ treated groups. The result also showed there were more negative effects by ion implantation into S. rebaudiana in N⁺ treated groups than those in C⁺ treated groups in the periods of seed germinating and plant growth.