Abstract: Manganese-copper composite(MCC) algaecide was prepared by permanganate and acid-soluble copper chloride. The effectiveness of MCC on microcystis aeruginosa removal and the effective period of MCC were studied, pH influence on the water sample was inspected, and the feasibility of MCC as a new algaecide was discussed. The results showed that the optimum ratio of copper reagent A and manganese reagent B was 0.5~1.5∶1.0. Removal rate of turbidity, OD₄₂₀ and chlorophyll a were 67.82%, 77.98% and 97.04% respectively during 10 days of MCC dosing. Turbidity and chlorophyll a were reduced to 6.16NTU and 1.048μg · L^-1, with removal rate of 77.4% and 99.48% after MCC dosing of 16 days. pH value of water sample was reduced with increasing ratio of copper reagent within MCC, pH value is 7~8 at the best composited ratio.