Diamond oil field are located in Block 01&02 Offshore Vietnam. Crude oil from Diamond Well Head Platform (WHP) is evacuated to FPSO via 20km - 10” subsea flexible pipeline. The lowest seabed temperature in the field is 220C, while pour point temperature of this crude oil is very high (360C) due to high parafin content (about 25% by weight). So studying to copolymerize a copolymer use to reduce pour point temperature of this oil is very important. The copolymer must have ability to reduce pour point temperature of the crude oil from 360C to 210C. The copolymer will be copolymerized from acrylate, methacrylate and vinyl acetate monomer. And there are many factors which impact on copolymerization reaction and therefore it will impact on the structure and performance of the said copolymer. One of the most important factor is a ratio of initiator with another component in the reaction. Therfore the aim of this research is to choose an appropriated ratio of initiator to produce a copolymer which can reduce pour point temperature of Diamond crude oil from 360C to 210C at dosage of 1.750ppmv.