In order to realize the optimal power flow under multiple time scales and multiple operation modes, the prediction results and power grid status are included in the optimization model simultaneously, and a power flow optimization strategy combining day-ahead and day-ahead optimization is proposed. According to the actual operation expectations, the objective function variable weight is adopted to adjust; The intra-day optimization combines the model predictive control system with super-short-term forecast, and plays the buffering role of energy storage to realize the tracking of scheduled distributed power output. In addition, give full play to the advantages of simplicity and high feasibility of knee search, and realize the global optimization of multi-objective optimization solution. The results show the practicability of this strategy.