The effects of continuous use and rotational use of insecticides on the resistance developing and the carboxylesterase activity of Myzus persice(Sulzer) were studied by simulating used in field. The results showed that resistance of M. persice treated by nine continuous spraying to omethoate，meyhomyl and λcyhalothrin increased respectively by 54.2fold，8.9fold and 10.4fold，and the activity of α-NA carboxylesterase increased respectively by 20.0fold，24.0fold and 43.2fold，and the individuals with enzyme activity of 0.6 eased respectively by73%，87.6% and 43.8%. The resistance of M. persicae treated by three rotational spraying to omethoate，meyhomyl and λcyhalothrin increased respectively by 38.0fold，6.7fold and 5.0fold，and the enzyme activity increased by 10.2fold. The individuals with enzyme activity of 0.6 increased by 4.8% after treated by three rotations in order of omethoate，meyhomyl and λcyhalothrin. The resultsproved that rotational use of insecticides can delay the resistance developing，and decrease the carboxylesterase activity and the individuals with higher enzyme activity.