In this paper, PAM was synthesized by photoinitiated polymerization. The methods of orthogonal design and uniform design were employed to optimize polymerization conditions, and the experimental data were manipulated by the mathematical analysis software SPSS. The effects of light intensity, the inner diameter of reaction vessel, rotation speed and reaction time for the polymer solution viscosity were explored. The results showed that the optimum polymerization conditions were described as follows: light intensity was 0.15 mW/cm2, the inner diameter of reaction vessel was about 36 mm, rotation speed was 10 r/min, and polyreaction 2 h. Finally we obtained that the relative molecular weight of PAM was more than 20 million.