Zwitterionic polyacrylamide, copolymerized by cationic monomer, acrylamide monomer and hydrolytic reagent, is a kind of water-soluble polyelectrolyte, which is nontoxic, tasteless, soluble in water easily and insoluble in organic solvents, such as ethanol and acetone. Due to cationic groups and anionic groups on its molecular chain, it could effectively decrease potential in water with the sludge and active adsorption groups in sewage via charge neutrality, adsorption-bridge and wrapping & winding functions, and make suspended particles and negatively charged water-soluble substances in water destabilize and flocculate to form relatively big flocculates to desposit or float upward. It is equipped with preferable dewatering property and metallic ion removal capacity, and the PH value is apply to a wide range, which is also widely used in range of application