The invention relates to a main wing surface structure of large aspect ratio wing, and belongs to the field of aviation. The main wing surface structure with the large aspect ratio comprises a honeycomb sandwich upper wall panel 1, a cap type reinforced lower wall panel 2, a box type main beam 3, a rear wall 4, a leading edge skin 5, a wing rib 6 and an adhesive 7. The honeycomb sandwich upper wall panel 1 is of a sandwich structure co-cured by carbon fiber composite inner and outer panels and a lightweight paper honeycomb. The cap-type reinforced lower wall panel 2 is of a cap type reinforcedstructure integrally cured by a carbon fiber composite skin and a foam core. The box type main beam 3 is of an integrated structure co-cured by adhering carbon fiber composite materials. The rear wall 4, the leading edge skin 5 and the wing rib 6 are of a carbon fiber composite press plate structure. The adhesive 7 is a room temperature curing paste adhesive. According to the respective bearing characteristics, each component adopts the corresponding structural form, which fully exerts the weight loss advantage of the composite material, and effectively solves the contradiction between the high load bearing and the light weight of the main wing surface structure of large aspect ratio wing.