Abstract: In order to maximize the critical buckling load coefficient, the ply stacking sequence and ply laying angle of laminated composite plate are optimized with improved simulated annealing algorithm in this paper. By using parallel computation and setting up double threshold the local optimal solution appeared in the process of optimization is avoided and meantime the rate of convergence is accelerated. Fiber laying angles and stacking sequence of composite laminates plate are chosen as design variables, and the design objective function is the critical compressive load. Comparative analyses show that the optimal ply stacking sequence and ply laying angle of laminated composite plate can be obtained with improved simulated annealing algorithm.