APAM was prepared under the action of composite initiator and UV irradiation, using acryl amide (AM), 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and acrylic acid (AA) as raw materials. The paper studied the effect of proportion between monomers, monomer ratio, initiator concentration and other factors on intrinsic viscosity of the polymer, and optimized preparation conditions. The chemical structure and thermal stability of APAM were characterized by UV, FTIR, SEM and DTA-TGA respectively. The results showed that the APAM with the intrinsic viscosity 1.6 x 10(3) mL x g(-1) can prepared when the proportion between monomers was 70 : 10 : 10, the monomer ratio was 40%, initiator concentration was 0.20%, pH was 9 and the illumination time was 60 min.