The invention discloses a central air-conditioning intelligent group control system, comprising a host, a cooling tower, a cooling pump, a central processor, and a data collector, a cooling reflux output temperature sensor, a freezing reflux output temperature sensor, a freezing reflux output pressure sensor, a controller connected with the central processor for reading the parameters of a frequency changer via on-site bus, and a network gate between the host and the controller. The sensor is connected with the data collector which can transmit the signal of sensor to the central processor. The invention uses several parameters to group control to fully utilize frequency change technique to reduce the abundant refrigeration most. And the invention uses the controller to on-time memory the data of air conditioner, to show variable power curvatures, watched and modified by user.