The monomer is dispersed in a micro-droplet suspension in the aqueous phase, and the oil-soluble initiator is dissolved in the monomer. Polymerization reaction is carried out in these droplets, the polymerization heat is absorbed in time by water, in order to ensure that these droplets in the water bead-like dispersion, need to add suspension stabilizer, such as gelatin, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, etc. The initiator uses organic peroxides and azo compounds, such as isopropyl carbonate, peroxide two cyclohexyl carbonate, dimethyl carbonate and Azobenzene, Azobenzene, Azo nitrile, and so on, and so on, and so on. Polymerization is carried out in a polymerization kettle with a blender. After polymerization, the material flows into the monomer recovery tank or the recovery monomer in the stripper. Then flow into the mixing kettle, washed and then centrifugal dehydration, drying of resin finished products. Vinyl chloride monomer should be removed from resin as far as possible. For food packaging PVC, free monomer content should be controlled under 1ppm. During polymerization, the temperature and pressure of polymerization process must be controlled in order to obtain the specified molecular weight and molecular weight distribution range of resins and prevent the coalescence. The particle size and particle size distribution of the resin are controlled by the selection and dosage of stirring speed and suspension stabilizer.