This study determined the effects of Probenazol on the activities of the defensive enzymes in rice plants and control effect against rice blast. The enzyme activity of PAL, POD and PPO in rice was higher than that in the control, and the enzyme activity is greatly increased with the increase of drug concentration after the 8% Probenazol G dressing; the growth rate of the defense enzyme activities and the high activity duration for the treatment with high concentration Probenazol were significantly higher than those of the control after the inoculation of blast fungus. The control effect of 8% Probenazol with the concentration of 300 g/m2 (the seedling disc dose) against rice leaf blast was 69.98%, that of fungicides 75% Tricyclazole (26.7 g per 667 m2) on the rice blast was 76.73%. Furthermore, the control effect of 8% Probenazol G with different doses against rice blast field trials was conducted, the results show that the control effect of 300 g/m2 (the seedling disc dose) against rice leaf blast and panicle blast were 75.74% and 66.26% comparatively, those of fungicides 75% Tricyclazole (26.7 g per 667 m2) against rice leaf blast and panicle blast were 82.05% and 71.64% respectively.