Abstract: ObjectiveNon-specific esterase(NSE)was measured for different species of mosquitoes at their different development,to provide insight into rational use of chemical insecticides and biochemical detection of insecticide resistance.MethodsMicroplate test of NSE was performed using B-Naphthyl acetate as the substrate and fast blue B salt solution as the colour agent.ResultsNSE activity varied significantly among 4 species of susceptible mosquitoes in both their larval stage and 3-day-old females.DDVP-resistant strain had higher NSE level than susceptible strain,and in both case,adult showed higher NSE level than Ⅳ-instar larvae,followed by Ⅰ-Ⅲ instar larvae.ConclusionDetect ion of NSE using Ⅳ-instar larvae or 3-day-old females can be used for insecticide resistance detection but with different criteria for different species of mosquitoes.