The invention discloses a method for participating in automatic generation control by controllable loads. Aiming at the conditions of increased adjustment complexity of a power grid and more diversified regulation and control means caused by the novel controllable loads in the power grid, the scattered controllable loads are aggregated and are enabled to be equivalent to virtual adjustable units whose outputs are negative values, parameters including an adjusting threshold and an adjusting range thereof are automatically calculated, the controllable loads are brought into a conventional automatic generation control system and participate in the adjustment of the power grid with other energies together, the automatic generation control is developed towards automatic power generation and consumption combined control, centralized cooperative control of the adjustable units of the whole grid is realized, the comprehensive regulation and control effect of the power grid is achieved to the maximum, and technical means is provided for interaction of the energies, the grid, and the loads.