Abstract: Path planning estimation method based on 6-DOF trajectory simulation is proposed. Analysis of several factor affect the path estimation is carried out and a 6-DOF trajectory model based on Simulink is put up. By simulation, actual response of flying parameters when aircraft follows the path planned is obtained, and rationality analysis for path planned from dynamic angle is put up. General estimation for planning effectiveness that comes from simulation is achieved. Simulation result indicated that the estimation method can actualize the validation of planned paths dynamic characteristic.