This article introduced the superwater’s action principle for controlling slime pulp and its virtues. And then it studied its bactericidal and ameliorative actions in close system of whitewater. The article also compared superwater with other conventional bactericides. At the use level, concentration, actuation duration and bactericidal ability, superwater system excelled conventional bactericides. Furthermore the superwater can improve a series of problems in close system of whitewater. At last, a pilot scale test about superwater system has been carried out in a packing paper company. The test indicated that the superwater in whitewater can increase yield and save cost.