Abstract: In order to provide a new way to preventing the Cladosporium red spot, it was significant to study of the effect of plant disease inducers on resistance induction against red spot of Paeonia delavayi.3 kinds of plant disease inducers that include Harpin, BTH and SA were been resistance test to red spot and the index of infection index, induced-resistance effects and related physiological and enzyme activity indexes were determined.The results showed that the 3 kinds of inducers had significant induced-resistance effects on the red spot and the infection index was dramatic decline.The optimal inducer was BTH and the best concentration was 100 mg/L that induced-resistance effect to the red spot was to be 68.27%.The indexes of SAFR and MDA were dramatic decline, but the indexes of soluble protein, Pigment and related enzymes activity were obviously higher than those control processing, what were closely related with resistance induction to the red spot.Three kinds of inducers hadn′t toxic activity to the Cladosporium paeoniae and could lead P.delavayi to produce systemic acquired resistance (SAR) effectively, which mechanism would have to be further studied.