The invention discloses a wide-area source-load day-ahead active optimization control method. The method comprises: relevant data of various power sources, centralized industrial loads and distributedcivilian loads are read; grouping aggregation processing is carried out on the distributed civilian loads; aggregation adjusting performance parameters of all groups of aggregation loads are calculated; a wide-area source-load day-ahead active optimization model is constructed and calculated to obtain day-ahead active power plans of the various power sources, centralized industrial loads and aggregated civilian loads; and day-ahead active power plans of all distributed loads among aggregated civilian loads are allocated. According to the wide-area source-load day-ahead active optimization control method, the adjustment characteristics of multi-mode elastic loads are considered fully; the characteristic analysis problem of the massive wide-area distributed loads are solved by means of aggregation; coordinated optimized control of the wide-area multi-mode elastic loads, conventional power supply and wind power is realized; and the absorption capability of the wind power by the grid is improved.