Abstract: A control law for formation keeping was designed using Lyapunov approach,and was optimized by genetic algorithm(GA).Then GA was improved to conquer the disadvantage of weak ability in local optimization.As a result,adaptive simulated annealing genetic algorithm(ASAGA) was developed.The simulation results show that after the optimization,the Lyapunov control law increases the position precision,consumes nearly the same quantity of fuel,and saves the computational time comparing with linear-quadratic regulation(LQR) approach,which is beneficial to implement by on-board computer system.