Based on previous missile trajectory optimization which optimized sectionally,design the pitch angle and the flight sequence of the tajectory integrally to make the missile lower and farther at the separation time of the 3rd stage engine.A dynamic model was built firstly.Then the optimization variables,the objective function and the restrictions were designed.The missile trajectory optimization was calculated and simulated with adaptive genetic algorithm.The simulation result shows that missile trajectory designed this way has lower altitude further range and better flight performance.