The effects of pinocembrin on the mycelia respiration of citrus blue mold(Penicillium italicum) were studied by clark oxygen electrode.The results showed that pinocembrin treatment significantly inhibited the mycelia respiration of P.italicum in a concentration-dependent manner.The inhibitory effect of mycelial respiration increased with the prolonging of pinocembrin treatment.When the treatment time was extended to 2 h,the inhibition rate was changed from 53.37 % to 84.35%.The inhibitory effect of pinocembrin on the respiration was most significant for young mycelia (cultured 12 h),and the inhibitory rate was up to 78.97%.With the increment of cell age,the inhibitory effect of pinocembrin on mycelia respiration declined.The respiration inhibitory rate of mycelia cultured for 60 h was only 29.25%.Results showed that pinocembrin treatment had an obvious inhibition on the mitochondria respiration of P.italicum at low concentration.Comparing synergistic inhibition of the typical respiratory inhibitors (antimycin A,rotenone,salicyl hydroxamic acid and sodium azide) and pinocembrin on the respiration of P.italicum,the results showed that pinocembrin and rotenone had the same pathway on the mycelia respiration of P.italicum.Therefore,pinocembrin had a significant inhibitory effect on P.Italicum by affecting respiration metabolism．