In this study, basalt scales were activated by air plasma and were subsequently deposited with cerium dioxide nanoparticles to obtain CeO₂-modified basalts (CB). Inspired by mussel biomimetics, polydopamine (PDA) and 3-glycidoxypropyltrimethoxysilane were further employed to modify the properties of CB to obtain functionalized basalt scales (CBD). This treatment greatly increased the interfacial compatibility between inorganic fillers and epoxy resin. At the same time, PDA can form chelates with iron ions in the anodic area to prevent further corrosion. Tensile, water absorption, and electrochemical impedance spectrum measurements showed that incorporating CBD into epoxy resins resulted in the composite coatings with higher mechanical properties, water penetration resistance, corrosion resistance, and lower wetting properties.