The invention discloses a wide area source-load day-ahead active power optimization control method. The method includes reading related data of various power supplies, centralized industrial loads anddistributed civilian loads; performing packet aggregation processing on the distributed civilian loads; calculating aggregation regulation performance parameters of aggregation loads of each group; constructing and solving a wide area source-load day-ahead active power optimization model to obtain a day-ahead active power plan of the various power supplies, the centralized industrial loads and aggregated civilian loads; and distributing the day-ahead active power plan of each distributed loads in the aggregated civilian loads. Adjustment characteristics of multiform elastic loads can be fullyconsidered by the method, and thus, the characteristic analysis problem of massive wide area distributed loads can be solved by using an aggregated manner, coordinated optimization control of wide area multiform elastic loads, conventional power supplies and wind power can be realized, and consumptive capacity of power grids on wind power can be enhanced.