Technologies, such as structural adjustment in water-oil production, polymer drive, pilot test insurfactant-polymer flooding etc. have been developed in Daqing oil field in order to maintain a long-term stableproduction period in its high water-cut production period. Sophisticated geological studies to identify thedistribution of remaining oil, especially in those low permeability layers, give a rational geological basis for thedevelopment of these technologjes. Accompanied technologies, such as detailed numerical reservoir simulationand oilfield management etc. have been developed successfully. All those technologies have been confirmed byfield practice to be very successful. Technologies, such as structural adjustment in water-oil production, polymer drive, pilot test insurfactant-polymer flooding etc. have been developed in Daqing oil field in order to maintain a long-term stable production period in its high water-cut production period. Sophisticated geological studies to identify the distribution of the remaining oil, especially in those low permeability layers, give a rational geological basis for the development of these technologjes. confirmed byfield practice to be very successful.