Abstract: Pesticides and heavy metals are two common types of pollutants in aquatic environment. The combined pollution is noteworthy because they posed a serious threat to aqua ecology and living environment for human. Herein, the acute toxicities of 3 common pesticides (chlorpyrifos, triazophos and fipronil) and 2 common heavy metals (Pb and Cd) to Daphnia magna were evaluated. Their combined toxicities were also studied using five-factor quadratic general rotary unitized design. The 48 h-EC50 values of chlorpyrifos, triazophos, fipronil, Pb2+ and Cd2+ to D. magna were 6.30, 7.27, 2.17, 454.91 and 1 175.74 μg/L, respectively. The contribution of these five pollutions to combined toxicological effects following the order: Cd2+ > triazophos > fipronil > chlorpyrifos > Pb2+. Combined effects of five pollutants was observed on the survival of D. magna. Moreover, the maximum theoretical synergy appears when chlorpyrifos was 0.811 μg/L, triazophos concentration was 17.22 μg/L, fipronil was 5.65 μg/L, Pb2+ was 83.75 μg/L and Cd2+ was 3 793.15 μg/L. The data of this study can provide support for the risk assessment of composite pollutants.