The project aims to study the blades of offshore wind turbines and structural materials for large aircraft, proposing to design and introduce structures with characteristic functional groups onto the surface of carbon nanotubes based on the structural characteristics of epoxy resin and bismaleimide (BMI) resins. By combining process adjustments with instrumental analysis, the quantity of characteristic functional groups is controlled to prepare a quality-stable multifunctional carbon nanotube modifier. Then, without changing the basic molding processes of carbon fiber/epoxy resin or BMI composites, this multifunctional carbon nanotube modifier is used to enhance the toughness, strength, modulus, erosion resistance, corrosion resistance, and aging resistance of carbon fiber/epoxy resin or BMI composites. The project provides a process flow and technical conditions for the industrial production of a multifunctional carbon nanotube modifier, preparing a multifunctional carbon nanotube modifier with stable surface functional group quantities. The research investigates its impact on the properties of composite materials. Prepares carbon fiber/carbon nanotube-epoxy resin composite materials and carbon fiber/carbon nanotube-bismaleimide resin composite materials with optimal strength, stiffness, toughness, erosion resistance, corrosion resistance, and aging resistance, completing the research on the mechanism of multifunctional carbon nanotube modifiers for enhancing the toughness of composite materials.