In order to investigate acute,chronic and joint toxicity of sublethal concentrations of endosulfan and dieldrin,the half-effect concentrations of endosulfan and dieldrin to Moina macrocopa were tested respectively,and the effects of endosulfan（0,52 and 208 μg/L） and dieldrin（0,12 and 48 μg/L） on the life table demography of the cladoceran were studied.The results showed that the EC₅0 values to endosulfan and dieldrin for M.macrocopa were 834.9 and 185.8 μg/L,respectively.The endosulfan concentration affected significantly the life expectancy at birth,generation time and net reproductive rate,but did not influence the intrinsic rate of population increase of M.macrocopa.The dieldrin concentration affected markedly only intrinsic rate of population increase.The interactions between endosulfan and dieldrin concentrations on all the life-table demographic parameters of M.macrocopa were not significant.Compared with those when the concentration of endosulfan was zero,endosulfan at 52 and 208 μg/L decreased markedly the life expectancy at birth,generation time and net reproductive rate.Compared with those when the concentration of dieldrin was zero,dieldrin at 48 μg/L increased the intrinsic rate of population increase of M.macrocopa.