Abstract：The Daqing Lamadian oil field has developed by basic well pattern, layer system adjustment pattern, producer injector adjustment pattern, secondary infilled well pattern, thick oil layer polymer flooding pattern, and polymer flooding upward pattern. Up to 2010, the PI1-2 layer has completely shifted to polymer waterflood in Daqing Lamadian oil field. With oil field developing, the oil layer waterflooding thickness and hierarchy increase. The water flooding situation becomes more and more complex. Through the analysis on coring well data change of property, water washing combining well logging curve characteristics and waterflooding explanation in different development stages, the evolution rules of lithologic character, petrophysical property, electrical property, and oil-bearing property are summed up in the process of water flooded reservoir. Based on the above results, thick oil reservoir water flooding regularity is summed up. The distribution of low waterflooding (washing) thickness is determined. It lays the foundation for further discovering potentials of PI1-2 oil layer; the anatomy of waterflooding main controlling factors provides the guidance for polymer flooding development in the sub-main layers.