Abstract: Series of amphoteric flocculants AAB with outstanding flocculation efficiency and salt tolerance were synthesized by dispersion polymerization using acrylamide(AM) as the main part and positive and negative charge groups as the monomers. The effects of the dispersion medium, stabilizer， monomer and chain transfer agent on the polymerization were investigated by determining the intrinsic viscosity of the copolymer and apparent viscosity. Meanwhile, the flocculation performance and salt resistance of the flocculants were evaluated by flocculation test. Then the optimum reaction conditions were determined as follows：n(AM)∶n(AA)∶n(DMBAC)=90∶5∶5, 13%(mass fraction) monomer, 0.2% VA-044 as initiator and 6% PDAC as stabilizer(based on the total monomer mass), 25% ammonium sulfate(based on the system), 500×10-6 sodium hypophosphite, 1000×10-6 sodium formate, polymerization temperature 35 ℃, polymerization time 24 h. Under the optimum reaction conditions, the amphoteric flocculants had the maximum intrinsic viscosity(for 5.2 dL/g) and better stability. All the results showed that the amphoteric flocculants exhibited excellent flocculation efficiency and salt tolerance due to the lower dosages(for 30×10-6) and the higher settlement rates(for 2.56 s-1) in simulated wastewater with high salt concentration.