Abstract: A multi-objective optimization problem is presented to deal with a Fowler flap used in high-lift devices of general aircraft. The purpose is to enhance its aerodynamic performance by searching for optimal shape and setting parameters for the flap. The procedure driven by the genetic algorithm based on non-dominated sorting (NSGA Ⅱ) method, elliptic equations, and RBF mesh deformation method is used to automatically generate the Fowler flap shape and compute meshes. Navier-Stokes solver is used for aerodynamic performance evaluation by distributed parallel computing that reduces optimization time cost. The Fowler flap optimization design based on GA(W)-1 airfoil is carried out to improve the lift coefficient in linear section of the lift curves(in the range lower than angle of attack 6°) and the maximal lift coefficient (near angle of attack 13°). The whole optimization process takes about 8 hours. The final Pareto optimal solutions are presented, and the correlation between design variables of the optimal airfoils is discussed. Compared with the baseline configuration, the maximal increments in lift coefficient at angle of attack 6° and 13° are 7.03% and 3.42%, respectively. These optimal results validate the high efficiency of the design optimization system proposed in this paper.