In order to obtain the angle of attack and the angle of sideslip of a missile, a method for calculating the angle of attack and the angle of sideslip of a missile based on the exterior trajectory and the attitude gyro information is proposed. The angle of attack and the angle of sideslip of the missile are calculated by calculating the trajectory angle and the trajectory deflection angle of the missile through the external trajectory of the missile and integrating the attitude gyro information on the missile, which are used to analyse the controlled characteristics of the missile and identify the aerodynamic parameters of the missile body, and further optimize the design parameters of the missile control system. The results show that the method is simple and effective, and it can be applied to the analysis of attack angle and sideslip angle of all guided munitions with attitude measurement device and external trajectory measurement.