Cationic polyacrylamide (CPAM) is a linear polymer compound. Because it has a variety of active groups, it can form hydrogen bond affinity and adsorption with a variety of substances. It mainly flocculates negatively charged colloids. In addition to the functions of turbidity, decolorization, adsorption and adhesion, it is suitable for the dehydration of sludge such as urban sewage, urban sewage sludge and industrial sludge in industries such as printing and dyeing, papermaking, food, construction, metallurgy, beneficiation, coal, oil field, aquatic product processing and fermentation.