This paper proposed an optimization design for a ride control system (RCS) for fast catamaran. The ship vertical motions are predicted by 2.5-D theory. The hydrodynamic characteristics of T-foil and trim tab are given, and the dynamic stability of the system is discussed. On this basis, the ride control system optimization model in regular and irregular waves is established for a specific catamaran. The optimal solution is obtained by using non-dominated sorting genetic algorithm-II (NSGA-II).