This study introduces an initiator system applied in the free radical polymerization of electron-deficient olefin，which uses two kinds of economic and environmental benign raw materials，namely H2O2 and FeCl3，and successfully realizes the free radical polymerization of water-soluble monomer like acrylic acid and methacrylic acid in water. Meanwhile，it also realizes the continuous aqueous precipitation polymerization of acrylonitrile in water and free radical polymerization in DMSO and DMF. The results indicate that at a relatively low initiator concentration and low reaction temperature （30~60 ℃），the molecular weight of sodium polyacrylate synthesized by the initiator system ranges between 1.0×106 and 2.0×106，while the molecular weight of sodium polymethacrylate ranges between 1.0×105 and 1.7×105，featuring low molecular weight distribution（Mw /Mn =1.1~1.4） and high conversion（>90%）；the molecular weight of polyacrylonitrile ranges between 2.0×104 and 8.0×104，and the conversion is as high as 94.1%.