Epoxy composite materials (ECMs) combine unique adhesive strength, heat resistance, and wear and corrosion resistance and are the basis for producing body components, sliding bearings, and protective coatings. To obtain epoxy composite materials, ÉD-20 epoxy resin, polyethylene polyamine as a curing agent, modifiers, and superfine reinforcements are used. Methods to control the structure and properties of ECMs with different reinforcement contents are justified, and structurization mechanisms depending on the nature and morphology of the ingredients and their ratios in the system are established. The structure and properties of epoxy composite materials depending on the reinforcement content are analyzed. Predominant factors that influence the properties of low-, medium-, and high-reinforced epoxy composites are identified. Additional ultrasonic treatment of composites in the formation stage is shown to be effective and improve the strength of the system owing to its higher homogeneity per microvolume, better wetting, and more active interaction at the interface.