The invention provides a water cooling system used for a feeding device of an incinerator. The water cooling system comprises a water cooling jacket which sleeves the feeding device, a water inlet pipeline which is connected to the water cooling jacket, a water draining pipeline which is connected to the water cooling jacket, a water temperature measuring device which is used for measuring the temperature of circulating cooling water inside the water cooling jacket, and a constant-temperature operating water valve which is connected to the water cooling jacket, wherein the constant-temperatureoperating water valve is used for controlling operation of the water inlet pipeline and the water draining pipeline; when the temperature of circulating cooling water is higher than a set value, theconstant-temperature operating water valve is opened, and the water inlet pipeline and the water draining pipeline start to work; and when the temperature of the circulating cooling water is lower than the set value, the constant-temperature operating water valve is closed, and the water inlet pipeline and the water draining pipeline stop working. According to the water cooling system disclosed bythe invention, the constant-temperature operating water valve controls operation of the water inlet pipeline and the water draining pipeline; it is guaranteed that a proper temperature is kept insideand outside the feeding device when the tempering temperature and the local temperature suddenly increase or when the incinerator is started; safe and stable operation of the feeding device is guaranteed; and the service life of the feeding device is prolonged.