Relatively high molecular weight of polyacrylamide(PAM) was prepared by photoinitiator(under) UV irradiation with arcylamide as monomer and water-soluble photoinitiator as initiator.The effects of reaction conditions on the polymer molecular weight such as the concentration of photoinitiator,monomer,Na_2CO_3,EDTA and pH were investigated.Chemical structures of the obtained PAM were characte-(rized) by FT-IR.Results show that PAM has excellent solubility and high purity,whose molecular weight could reach 1.7×10~7.