The capacity of the high power pulsed-UV light system was evaluated in terms of removing THMs, geosmin and heterotrophic bacteria in water. The operating conditions of the system were irradiation distance; 10cm, operation voltage; 1,720V and irradiation time; 10min. The removals of THMs, chloroform, bromodichloromethane, dibromochloromethane, bromoform and geosmin were 59.0%, 46.9%, 76.7%, 100.0%, 100.0% and 95.4% respectively. The removal of heterotrophic bacteria was 3.7log in case of irradiation distance; 20cm, operation voltage; 1,500V, and irradiation time 2min. The system was also investigated for its ability to reducing free residual chlorine. The removal efficiency could be improved by increasing the operation voltage, the operation time, number of lamp and the length of the lamp.