A carbendazimsusceptible isolate and a carbendazimresistant isolate of Botrytis cinerea were compared with regard to mycelial growth and the extreme value of conductance upon treatment with the benzimidazole fungicide carbendazim hydrochloride. The result showed that the EC50 value of carbendazimsusceptible isolate was 0.062 0 mg/L, while the carbendazimresistant isolate formed normal colony on PDA containing 1 000 mg/L carbendazim hydrochloride. Under the treatment of carbendazim hydrochloride with the concontration of 5 or 10 mg/L,the conductivity of carbendazimsensitive isolate showed a decreasing tread,but that of carbendazimresistant isolate only changed a little.