Toxicity of polymer, Alum, Zeolite, Loess, Koalinite and Chitosan on earthworm and the effects of sewage sludges coagulated by several mixtures of those coagulants on the population growth of earthworm Eisenia andrei were evaluated. Under the concentration of 20,000 mg/L of Zeolite, Loess and Kaolinite, and under 1,000 mg/L of Chitosan were there no acute toxicities on earthworms. The concentration of Polymer over 160 mg/L showed acute toxicity upon earthworm, but the concentration under 80 mg/L showed no toxicity. The concentration of Alum over 125 mg/L showed acute toxicity. The mixture of ‘Polymer 80 mg/L + Kaolinite 500 mg/L + Chitosan 20 mg/L’ had higher coagulating efficiency than the ‘Polymer 80 mg/L + Kaolinite 500 mg/L’ on sewage sludge, And the sewage sludge coagulated by former mixture induced higher growth rate of earthworm population than that coagulated by latter mixture when the sewage sludges were supplied to earthworms.