Abstract: In view of the increasing trend of renewable energy generation and flexible resources in the power grid, a robust optimization method for day-ahead dispatching considering the flexible resources of both source and load sides is proposed to cope with the challenges brought by the uncertainty of renewable energy generation to the dispatching operation of the power grid. Firstly, according to the response characteristics of reducible loads and shiftable loads, the influence of compensation price on the maximum reduction capacity of the former and the acceptable translation period of the latter is analyzed, and the flexible resources model of load side is established. Secondly, considering the uncertainty of wind power output, based on the model of deep peak regulation and flexible resources on load side, a robust optimization model for day-ahead dispatching is established, in which the compensation price and adjustment quantity of flexible loads are jointly optimized. Finally, the effectiveness of the proposed model and method is verified by an example analysis. The results show that the dispatching method considering the schedulable potential of flexible resources of both source and load sides can effectively improve the robustness and economy of power grid operation.