The invention discloses an automatic demand response system and an automatic demand response method. The system comprises an EDR (Equipment Demand Response) controller, a multi-protocol communication gateway, a DR (Demand Response) client and a DRAS (Demand Response Automation Server), wherein the EDR controller is connected with the DR client through the multi-protocol communication gateway, and the DR client is connected with the DRAS. The EDR controller collects electric power data of each electric load device, distributed energy source and an energy storage device, and transfers the electric power data to the DRAS through the DR client. The DRAS sends the electricity price information set by a DR center and demand response events to the DR client. The control measure is made by the DR client, and the EDR controller controls the running states and the running modes of each electric load device, the distributed energy source and the energy storage device according to the control measure. The automatic demand response system and the automatic demand response method provided by the invention have the advantages of accurately balancing the power grid load in real time, reducing the impact of new energy on-grid on a power grid, and improving the stability of the power grid.