In this study, a kind of anionic polyacrylamide (P(AM-AA-AMPS)) was synthesized using acrylamide (AM), acrylic acid (AA), and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) under ultraviolet (UV) irradiation. The conditions of the polymerization reaction such as monomer mass ratio, solution pH value, EDTA concentration and urea concentration were investigated by using the single factor approach and an L16 (45) orthogonal array. The structure and morphologies of the copolymer were determined by nuclear magnetic resonance spectrometer (NMR), infrared spectrometer (IR) and scanning electron microscope (SEM). The results show P(AM-AA-AMPS) with the intrinsic viscosity of 1.5 x 103 mL g1 was synthesized at optimal conditions: mass ratio, m(AM) : m(AA) : m(AMPS) of 70 : 10 : 10, pH value of 9.0, EDTA concentration of 0.10% and urea concentration of 0.20%. In addition, P(AM-AA-AMPS) had better flocculation efficiency than commercial PAM in sludge dewatering experiment; the minimum filter cake moisture content could be reduced to 65.1%. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013