The development of the wing of suborbital reusable spaceplane is a complex task due to conflicting requirements that are sufficient for its structure. They include high mass and cost efficiency, sustainability, low g-forces, effective heat protection under the consideration of technological restraints. To satisfy outlined requirements in the design of the composite wing the inter-disciplinary approach is presented relying on advanced methods of mathematical modelling. The approach starts with wing shape optimization enabling to get good aerodynamic performance. Subsequent optimal re-entry trajectory planning which use both angle-of-attack and angle-of-bank changes to control the re-entry provides a set level of g-forces and heat flux. Then based on the obtained trajectory the aerodynamic loads for the wing are gained. To acquire composite materials properties of the wing the analysis/test approach is applied that comprises multilevel modelling of mechanical and thermal material properties by commercial software. The results of modelling are validated by experiment. In addition, to enhancing mass efficiency of the wing structure the topology optimization of its wing box and structural optimization of the wing skin is conducted which uses both angles of orientations and thicknesses of composite monolayers as the variables with constraints on the strength and stiffness of wing skin. Furthermore, the approach includes thermal design due to high aerodynamic heating taking place during re-entry. Thermal loads are analysed by modelling the thermal state of the structure. The analysis showed that the wing skin needs thermal protection. As the thermal protection coating, the material based on glass microspheres was chosen. Its thickness through wing is obtained in the result of parameter optimization. As the result, the interdisciplinary approach to the design of the spaceplane composite wing is developed that allows feeding back mass, economic, aerodynamic, heat and strength impact into the spaceplane wing design synthesis.