This paper presents a new particle swarm optimization( PSO) algorithm to optimize the trajectory of morphing-wing missile so as to achieve the enlargement of the maximum range. Equations of motion for the twodimensional dynamics are derived by treating the missile as an ideal controllable mass point. An investigation of aerodynamic characteristics of morphing-wing missile with varying geometries is performed. After deducing the optimizing trajectory model for maximizing range,a type of discrete method is put forward for taking optimization control problem into nonlinear dynamic programming problem. The optimal trajectory is solved by using PSO algorithm and penalty function method. The simulation results suggest that morphing-wing missile has the larger range than the fixed-shape missile when launched at supersonic speed,while morphing-wing missile has no obvious range increment than the fixed-shape missile at subsonic speed. This paper presents a new particle swarm optimization (PSO) algorithm to optimize the trajectory of morphing-wing missile so as to achieve the enlargement of the maximum range. Equations of motion for the twodimensional dynamics are derived by treating the missile as an ideal controllable mass An investigation of aerodynamic characteristics of morphing-wing missile with varying geometries is performed. After deducing the optimization trajectory model for maximizing range, a type of discrete method is put forward for taking optimization control problem into nonlinear dynamic programming problem. The optimal trajectory is solved by using PSO algorithm and penalty function method. The simulation results suggest that morphing-wing missile has the larger range than the fixed-shape missile when launched at supersonic speed, while morphing-wing missile has no obvious range increment than the fixed- shape missile at subsonic speed.