Abstract: Through analyzing the kinds，concentrations and toxicity of heavy metals in wastewater，the paper selected Cu，Zn and Cr as objects，and investigated the impact of these three metals on activated sludge system，including microbial species， growth，substrate consumption and performance of wastewater treatment plant． The factors were analyzed that affecting heavy metal toxicity on activated sludge like the kind and concentration of metal，process types and domestication． Some feasible measures for treating heavy metal containing wastewater were summarized: Employing SBＲ process to resist shock load; making use of acclimated sludge; increasing the concentration of sludge． Finally，the study proposed several possible research directions in this field．