Abstract: The effect of insecticides are closely related to the composition of population and different physiological states of elm leaf beetle(Galerucella aeneseens F.)and to temperature and humidity changes in the field. (1) The insecticidal resistance in different physiological states is as follows:(a).larval stage—lst instar<2nd instar<3rd instar<ripe larval;(b),adult stage—newly emerging adult<over wintering adult in flight period<adult in stage of supplement of nutrjtion<adult in the preparatoryperiods for passing summer. (2) Influence of seasonal changes on temperature on insecticidal efficiency:at lower temperature,DDT have quicker killing effect and stronger in efficiency than Dipterex and vice versa;at higher temperature,effect of Rotenone a little weaker than that of Dipterex,although they are similar in nature. (3) Influence of diurnal changes in temperature and humidity on insecticidal effifiency:spray was made in the morning and at noon when temperatures and humidities were reversed respectively.During and after spraying the temperature and the humidity have a direct effect on killing speed of various insecticides,however,within certain range of temperature(20—30℃),it has little influence on final mortality.