An energy-saving optimization method for an oilfield flooding system belongs to the technical field of computer programs. The energy-saving optimization method comprises the following steps: 1, collecting data of the oilfield flooding system, drawing a pipe network distribution diagram, marking the topographic condition, establishing a steady and dynamic mathematical model of the oilfield flooding system, and calibrating according to the actual operation condition; 2, drawing optimization curves between main pressure and total energy consumption, between main pressure and under-injected well numbers, between main pressure and the total operating expense and the like through simulating the operation condition of a model under different main pressure according to the established mathematical model; 3, integrating a plurality of models into a system by applying a VBA technology and an ASW platform according to the established steady and dynamic mathematical model, transmitting the calculation result in the mathematical model to a user interface in real time to realize the every-saving optimization analysis, and developing a plant-level operation interface, a water injection station-level operation interface and a water distributing station-level operation interface, which are operated by a user; 4, developing a data interface by applying SQL, transmitting data in a database to the mathematical model in real time, and maintaining the synchronization of the model and the actual production.