The effects of temperature, initial Pb^2+, concentration and initial sludge concentration on the initial Pb^2+ removal rate and maximal Pb^2+ removal amounts in activated sludge, respectively, were investigated. The removal of Pb^2+ in activated sludge was proved to be temperature-dependent process. The initial Pb^2+ removal rate increased from 187.5 to 261.4 ㎎ Pb^2+/g sludge dry weight·min, in response to the promoted temperature from 10℃ to 60℃, while the maximal Pb^2+ removal amount (78.5 ㎎ Pb^2+/g sludge dry weight) occurred at 30℃. As the initial Pb^2+, concentration increased from 36 to 228 ㎎ Pb^2+/L at the constant temperature of 30℃ and initial sludge concentration of 1.5 g sludge dry weight/L, the time to reach an equilibrium state was almost independent of the initial Pb^2+ concentration and the equilibrium Pb^2+ removal amount was increased from 41.9 to 73.6 ㎎ Pb^2+/g sludge dry weight. On the contrary, the equilbrium Pb^2+ removal amount was decreased from 87.7 to 65.3 ㎎ Pb^2+/g sludge dry weight as the increase of initial sludge concentration from 0.22 to 1.76 g sludge dry weight/L.