A system for controlling a plurality of power generation plants. The system comprises at least three display-input means for displaying process data of the power plants and for inputting signals for operating the power plants based on the displayed process data, and the display-input means are disposed in a central control room. The system also comprises allocation means for allocating at least one of the display-input means to each one of the power generation plants, based on operation phases of the power generation plants. The system also comprises moving means for moving at least one of the display-input means so that a plurality of groups of the display-input means are formed, and the display-input means of a same group be arranged closer to each other than the display-input means of different groups.