Provided is an electrolytic disinfection system and method for purifying water. The electrolytic disinfection system includes; an electrolytic disinfection device which includes; a chamber, a first electrode disposed in the chamber, a second electrode disposed in the chamber and spaced apart from the first electrode, a water inlet part connected to the chamber, wherein the water inlet part allows influent water to be introduced to the chamber therethrough, and a water outlet part connected to the chamber, wherein the water outlet part allows the influent water to be discharged from the chamber therethrough, and an influent water heating device which is disposed upstream of the water inlet part and heats the influent water introduced to the chamber through the water inlet part.