Chengdao oilfield has entered middle-high water cut stage. Due to the influence of strong reservoir heterogeneity，uneven waterline rush，serious interference of production in multi-well groups and the imbalanced displacement of injected water in the underground directly affect the overall development effect of the reservoir. Therefore，a vector optimization method for reasonable liquid production and water injection rate was proposed. Concept of displacement breakthrough coefficient was established，and equilibrium displacement limit was determined to be 3. The actual reservoir displacement was divided into 4 modes. Reasonable fluid production and water injection rate of oil-and-water wells under different displacement modes was determined，and thus the goal of balanced reservoir displacement could be achieved. This method was applied to field liquid increase test in seven well groups of Chengbei 11N well block. By the end of December 2015，incremental cumulative oil was 2.7×104 t，and recovery rate was increased by 5% in the evaluation period（15 a）.