Abstract: Total count of bacteria and total coliforms group were applied as the monitoring index, and the secondary effluent from urban wastewater treatment plant were employed as water samples in this study. The disinfection efficacy by chlorine or chloramines individually or combination of potassium permanganate and chlorine were investigated in wastewater treatment process, and the control effect of trihalomethane formation was surveyed also. The feasibility of practical application on synergistic disinfection of potassium permanganate and chlorine was investigated on both aspects of chemical safety and microbial safety. The results show that chlorine disinfection have no advantage compared with chloramine disinfection for seriously polluted wastewater, especially with higher concentration of organic nitrogen and ammonia nitrogen. The disinfection efficacy of synergistic disinfection of potassium permanganate and chlorine is improved distinctly than that of chlorine disinfection individually, and trihalomethane formation is clearly less too. Therefore, both aspects of chemical safety and microbial safety of treated water can be improved by synergistic disinfection of potassium permanganate and chlorine process.