Anionic polyacrylamide(APAM) series products are water-soluble linear polymers synthesized with high polymerization degree, easily soluble in water, almost insoluble in benzene, ether, lipids, acetone and other general organic solvents. The anionic polyacrylamide produced by Xinhuan Water Treatment can be used as coagulant aid, retention agent, sludge dewatering agent and coagulation precipitant. Because its molecular chain contains a certain number of polar groups, it can adsorb the suspended solid particles in water, make the bridge between particles or make the particles coalesce to form large flocs through charge neutralisation, so it can accelerate the settlement of the particles in the suspension, and it has the effect of accelerating the clarification of the solution and promoting the filtration, etc.