A waste salt solution impurity removal agent metering device comprises a graduated metering container (2) and a feeding pipe (1), the feeding pipe (2) is arranged above the metering container (2) and is connected with the metering container (2) through a feeding valve (6), the side surface of the metering container (2) is provided with an exhaust pipe (3) through a control valve (5), and the bottom of the metering container (2) is connected with a discharging pipe (4) through a discharging valve (7). The waste salt solution impurity removal agent metering device has the advantage of being capable of effectively controlling added solution volume in batches, thereby guaranteeing accurate dosages of raw materials and auxiliary materials for production.