The annual ginseng seedlings were treated with three concentrations of Rhizoctonia solani toxin. The activity of the superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and malondialdehyde (MDA) content were measured after 0, 1, 3, 6, 12, 24h treatment respectively. The results showed that the effects of Rhizoctonia solani crude toxin on defensive enzyme activity in ginseng seedling firstly increased then decreased, MDA level is remained high, and continued rising.