A method called wake integration for the aerodynamics evaluation was discussed. Based on Euler equations to get the fluid field solution, this method applies the momentum theorem to a control volume that encloses an aircraft and it is improved from the traditional far field integration method. By doing integral computation on the wake surface that is down from the aircraft and vertical to the velocity of far field, it can get the lift, induced drag, wave drag and the total drag. This method is advantaged to the aerodynamics calculation for the aircraft having the complicated configuration and it can decompose the total drag by physical causes. Consequently the designer can be aware of more details about the aerodynamics of the configuration in the design. Some methods to improve the accuracy and efficiency of wake integration were discussed. The results of the computation demonstrate that the method and improved technique are correct and useful in the aircraft design.