The high molecular weight PVAc was prepared via an emulsifier-free emulsion polymerization, by using redox initiator system. The PVAc was then hydrolyzed to high molecular weight PVA. The influence of polymerization condition on molecular weight and distribution of PVAc is studied, such as the polymerization temperature, initiator concentration and conversion of monomer. The control method of structure of linear high molecular weight PVA is discussed. The results show that the PVA with DP=9899 can be gotten...