Recently, CNOOC launched the EOR with chemical flooding on more and more offshore oilfields in Bohai Bay in china. With the useful life of platform and the present production state, polymer flooding is considered as an important technology for the strategic development of offshore heavy oil fields in Bohai bay. Up to 2010, there are 3 polymer EOR projects on heavy oil field which the water cut is between 10 – 80%. And about 20 thousand tons polymer powder was used in 27 wells in the past 5 years. It has been seen that the water cut declined while the oil production increased. The application result shown it is feasible. The history of polymer EOR in Bohai Bay was present in the paper.