Abstract: Inhibitory activity of natamycin and diethofencarb to Botrytis cinerea Pers.under different temperatures was tested by mycelium growth rate method.Mycelial leakage of sugar,protein and electrolyte was tested by liquid cultivate method indirectly.The results showed that EC50 values of natamycin were 37.42 μg/mL in 25℃,and 0.984 0 μg/mL in 5℃,increased 37-fold.The activity of diethofencarb to B.cinerea increased 5-fold.Eight hours after treated by natamycin,the sugar leakage was 6.5 mg/g,the protein leakage was 162 μg/g and the conductance was 700 μs/cm.All of these were higher than that treated by 0.1% tween-80(CK) and diethofencarb.The mycelial leakage decreased as the temperature fell down.