Abstract: A new environment-friendly TBHP-Fe²⁺-SoE (sodium erythorbate) redox initiator system was applied instead of traditional H₂O₂-Fe²⁺-ZFS or H₂O₂-ZFS systems for the emulsion polymerization of vinyl acetate and ethylene. The initiation efficiency of the TBHP-Fe²⁺-SoE and the H₂O₂-Fe²⁺-ZFS systems was compared, and the effects of components concentration in the system and the feeding rate of TBHP solution on the polymerization kinetics were investigated. The results show that the initiation efficiency of the TBHP-Fe²⁺-SoE system is similar as that of the H₂O₂-Fe²⁺-ZFS system when the reaction temperature is 80℃. Active radicals are produced by the reaction of TBHP and SoE, which increase by addition of small amount of Fe²⁺. The initiation efficiency of the TBHP-Fe²⁺-SoE system increases with the increase of Fe²⁺, TBHP/SoE molar ratio and TBHP feeding rate. The system exhibits the highest initiation efficiency when the concentration of the TBHP-Fe²⁺-SoE redox initiator system is 0.25% of the total VAc monomer weight.