The invention relates to an automatic demand response device oriented to a central air conditioning system and an application method. The automatic demand response device is arranged on the side of the central air conditioning system and located between the central air conditioning system and a demand response server on a power grid side. The automatic demand response device comprises a data storage module, a man-machine interaction module, a communication module, a safety module, a separation module, an interface module, a real-time clock, a watchdog and a power management module which are arranged in an outer shell and are in communication with a microprocessor module. Coordination control over operation loads of the central air conditioning system in demand response services is achieved by executing corresponding strategies in the data storage module. Through the device and the application method, the execution efficiency of the automatic demand response services is improved, the load adjusting mode of the central air conditioning system under a traditional manual intervention mode is changed, and human resources and economic costs are reduced.