Using 2-acrylamide-2-methyl propane sulfonic acid (AMPS), itaconic acid (IA), and N-vinyl-2-pyrrolidone (NVP) as monomers, a new retader terpolymer AMPS/IA/NVP (PAIN) was synthesized by free radical aqueous solution copolymerization and characterized by FTIR and H-NMR. Through the orthogonal experiment, the optimum reaction conditions of copolymerization were obtained: NVP 7.5 wt (mass fraction) %; regulator V 4%; reaction temperature 60 degrees C; initiator 1 wt %. The intrinsic viscosity number of PAIN synthesized with different amount of regulator (isopropanol) was determined, finding that the regulator can change the molecular weight and distribution of PAIN. Through the thickening experiment in high temperature and high pressure, it was found that PAIN had an excellent retardation property in high temperature, and the thickening times of the cement slurries with 1% (BOWC) PAIN were up to 256 min at 110 degrees C and 234 min at 130 degrees C, respectively. The PAIN was even stable when the temperature below 350 degrees C proved by TG-SDTA analysis. Moreover, the retarding mechanism of PAIN was analyzed and discussed. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 2951-2957, 2010