Abstract: A simple calculation method is proposed in this paper to quickly and accurately predict the design maneuver load of an aircraft in the preliminary design stage. Aerodynamic derivatives of the aircraft are calculated based on the static aeroelastic theory, and the maneuver simulation of aircraft is carried out with the aerodynamic derivatives, the control characteristics and the mass characteristics as the input. The time history of each motion parameter is obtained. Finally, the distributed load on the components is calculated by the vortex lattice method. The results of this paper are compared with those of traditional methods. It is shown that this method is accurate and reliable, and can meet the load requirements of the aircraft design in the preliminary design stage. This method can effectively overcome the shortcomings of the traditional method which needs a large number of data of aerodynamic characteristics and pressure distribution to be obtained in wind tunnel tests. With the method in this paper, calculations can be carried out with fewer input parameters, which can save time and speed up the development of the model.