The diamond oil field is located in Blocks 0102 Offshore Vietnam. Crude oil from Diamond Well Head Platform (WHP) is evacuated to FPSO via 20 km - 10” subsea flexible pipeline. The lowest seabed temperature in the field is 22˚C, while the pouring point temperature of this crude oil is very high (36˚C) due to high paraffin content (about 25% by weight). So studying to synthesize a copolymer use to reduce the pour point temperature of this oil is very important. The copolymer must have the ability to reduce the pour point temperature of the crude oil from 36˚C to 21˚CThe synthesis process occurred via copolymerization of acrylate, methacrylate and vinyl acetate monomers using the free radical polymerization method in Solvent 100 as a solvent. There are many factors that affect copolymerization reaction and therefore they will impact the structure and performance of the said copolymer. One of the most important factors is the ratio of initiator to monomer in the reaction.Therefore the aim of this research is to choose an appropriated ratio of initiator to produce a copolymer that can reduce pour point temperature of Diamond crude oil from 36˚C to 21˚C at a dosage of 1.750ppmv