The invention provides a control system of an energy storage power station, and a communication method of the control system. The control system comprises a central controller and a plurality of energy-storing containers. The energy-storing container comprises a first energy-storing container and a plurality of second energy-storing containers. The first energy-storing container comprises a mastercontroller and a slave controller, and each second energy-storing container comprises a slave controller. The central controller, the master controller and each slave controller respectively comprisean EtherCAT communication module, which enables the central controller and the master controller, and the master controller and each slave controller to communicate through the EtherCAT protocol. Theinvention is advantageous in that the response of the central controller can be improved; the synchronization among the energy-storing containers can be increased; the demand of power grid can be metat the same time, and the stability of power grid can be improved.