It can improve the retention rate of fiber, filler and other chemicals, bringing clean and stable wet chemical environment, saving the consumption of pulp and chemicals, reducing production costs, and improving paper quality and paper machine production efficiency. Good retention and filter agent is the prerequisite and necessary factor to ensure the smooth operation of the paper machine and good paper quality. High molecular weight polyacrylamide is more widely suitable for different PH value. (PH range 4-10)