A coach apparatus and a cooperative operation controlling method for a coach-driven multi-robot cooperative operation system are provided. The coach apparatus connects with a plurality of action robots and receives state space data from each action robot. The coach apparatus divides the action robots into a plurality of action group. The coach apparatus reduces the state space data of the action robots in each action group to generate reduced state space data of each action group, and trains and builds a cooperative model based on the reduced state space data. In addition, for each action group, the coach apparatus selects a group strategy based on the reduced state space data, and transmits the cooperative model and the group strategy to the action robots in the action group to make them carry out an action mission according to the cooperative model and the group strategy.