Irregular well network with high oil recovery rate is used in the development of offshore oilfield, which usually leads to imbalanced waterflooding and poor development performance. In this paper, according to the Buckley-Leverett Equation and general waterflooding theory, a quantitative relationship between water-cut, liquid production and water injection rate is gained to improve the unbalanced lateral waterflooding of the present well network. All the single-well water-cuts are considered to obtain balanced waterflooding of present well network through liquid production and water injection rate adjustments. A new injection-production adjustment method is proposed, with the corresponding calculation program being compiled to realize real-time optimization and adjustment. This method is applied to the 1-1195-1 sand body of Bohai BZ Oilfield. The daily oil increment is 80 m³/d and the cumulative annual oil increment is 2.6×10⁴ m³, which is consistent with the expected program. It can therefore contribute to engineers' optimizing the injection-production strategy of reservoirs, as well as facilitating revitalizing mature water foods and, more importantly, facilitating the design and implementation of an appropriate Improved Oil Recovery pilots. The presented reliable method could provide certain significance for the efficient development of offshore oilfields.