Abstract: The synergistic antibacterial effect of three compound essential oils ( cinnamaldehyde / citral, cinnamaldehyde / eugenol, citral / eugenol) on Botrytis cinerea was studied through mycelial growth rate method.The synergistic antibacterial mechanism was preliminarily analyzed through measuring the cell constituent release and cell membrance potential. The results indicated that the antibacterial effect of the compound essential oils on postharvest Botrytis cinerea was higher significantly ( p < 0.05) than the individual treatment.And the cell constituent release and cell membrance potential was higher significantly ( p < 0.05) . The 500μL / L cinnamaldehyde / citral had the best effect. During the time of culture, EC50 was 67.46 ~ 101.31μL / L for cinnamaldehyde / citral. The antibacterial effect of cinnamaldehyde / citral was the most stable. The antibacterial effect rate was 93.75%. The synergistic antibacterial effect of cinnamaldehyde / citral could destruct the cell membrane of Botrytis cinerea. Due to the outflow of cell constituent and ion the cell of Botrytis cinerea died.