Abstract: Effect of eugenol on mycelial membrane of Botrytis cinerea was studied.The results showed that eugenol could cause damage to cytoplastmic membrane including induction of lipid peroxidation and membrane disruption,alteration of membrane permeability and leach out of MDA.Further study showed that the content of H2O2 in mycelia increased after treatment with eugenol,and a remarkable increase of the concentration of Ca2+ in mycelia within 30 min and thereafter decrease was observed.It was speculated that the efflux of Ca2+ was attributed to the damage of cytoplastmic membrane.Meanwhile,the result of DNA electrophoresis suggested that eugenol may not induce apoptosis of cell of B.cinerea.