Abstract:In order to reveal the antibacterial mechanism of paeonol in the peony, the inhibition of mycelium growth was measured by the growth rate and the effects of spore germination and formation were measured by coating plate in tests. The results showed that paeonol content to the relative inhibiting rate of the linear growth of fungal colony diameter and mycelia biomass yield was positively correlated, when Rhizoctonia cerealis and Fusarium solani were cultured for five days in paeonol content 0.08, 0.4mg/mL medium culture, the inhibiting rates of dry weight of mycelium were 79.81% and 55.08%. Paeonol had no effects on germinating rate for the spores, but germ tubes became swollen at the apical, basal and middle. Paeonol delay the time of formation for conidiophores and reduce the number of the spores. Gibberella zeae and Fusarium solani were cultured for ten days in 0.20, 0.24mg/mL PSA medium, the inhibiting rates of the spores were 100% and 33.33%.