Abstract: Through years of development and production, a waterflooded oilfield of Bohai has entered into the stage of high water cut oil production, with comprehensive water cut reached 71%, facing many serious problems such as reservoir pressure depletion and oil layer being water flooded. The remaining oil distribution became local enrichment. In comprehensive adjustment phase, by optimizing the well pattern, degree of single well control has been improved. During the completion operations, by means of reservoir protection, perforation parameters optimization, choice of reasonable negative pressure value, a trip to multi-layer gravel packing technology and other specific technical measures, the oilfield development effects and recovery by water flooding have been improved effectively, which provided reference and guidance for further exploring the potential of high water cut oilfield and improving the overall degree of development.