Abstract: The study of static aeroelasticity is of significant importance for the aerodynamic and load design of aircraft. At present, numerical computation and wind tunnel testing are the principal methods for studying static aeroelastic problems. In this work, the wind tunnel test method for high-speed static aeroelastic load of civil aircraft with large aspect-ratio and high flexible wings is systematically investigated. On this basis, the influence of static aeroelastic effect on the wing load is thoroughly studied. Experiments confirm that the static aeroelastic effects of a high flexible wing with large aspect ratio can produce a load reduction effect. The experimental results show that within the range of 0 °～6 ° angle of attack, the wing bending moment elastic stiffness ratio is smaller than the wing shear elastic stiffness ratio, confirming that the static aeroelastic effect of a high aspect ratio flexible wing can effectively reduce the wing bending moment while maintaining constant wing shear. The maximum deformation of the wing tip exceeds 200 mm by flow field visualization. Negative torsion occurred near the wing tip due to elastic deformation, reducing the local angle of attack, thereby reducing the shear force, bending moment, and torque at the wing root. The present results provide the load design basis for large aspect-ratio and high flexible wings.