Abstract: Aiming at biosafety problem in the domestic hot water system (DHWS), the inactivation efficiency of biofilm microorganisms on the living hot water pipeline wall by the disinfection methods of silver ion, thermal energy and silver ion-thermal energy compound impact disinfection technology was comparatively studied. The results show that, the concentration of silver ion and the temperature of the hot water have a significant influence on inactivation of the total number of bacteria and Escherichia coli of the biofilm on the DHWS pipeline wall. The effect of silver ion-thermal energy compound impact disinfection technology is better than that of single silver ion disinfection or thermal energy thermal energy significantly. The effect of compound impact disinfection technology with 60℃ hot water, 0.05 mg/L silver ions and 60 min of disinfection is close to single thermal energy disinfection technology of 70℃, but the disinfected biofilm becomes thin and shed, and biofilm structure is damaged significantly. And the silver ion-thermal energy compound impact disinfection technology can significantly improve the inactivation effect of biofilm microbes on the wall of DHWS pipeline and can kill the pathogenic microorganisms efficiently, which is a valuable technology for safety disinfection and water quality protection of DHWS.