Abstract: The result of the bioassay against Puccinia striiformis f·sp·tritic showed that DIMBOA would have effect on inhibiting the germination of the sporangium. At 1.0mg/ml concentration, its inhibiting rates can reach 79.31%; At 0.6~0.8mg/ml concentration, its inhibiting rates can reach 32.67%~44.08%. The potexperiment showed that DIMBOA has protective efficacy and therapeutic efficacy at 0.2~1.0mg/ml concentration; and its protective efficacy are better than therapeutic efficacy.