Due to the volatilization of solvent and erosion of waterborne corrosive medium, the diffusion gap of pure epoxy coating inevitably appears, reducing the barrier performance. The addition of inorganic pigment can block the diffusion gap, effectively improve the barrier performance and even the mechanical properties of the composite coating. However, the inorganic pigments without treatment have poor compatibility with resins and obvious tendency to agglomerate. In the composite coating, the resin matrix/pigment interface is an important microstructure which has a crucial influence on the physical, chemical and mechanical properties of the composite coating. The work aims to investigate the effect of the chopped basalt fiber/resin matrix interface on properties of the composite coating, and improve the comprehensive properties of the composite coating through regulating the interface structure by acid etching, activation treatment, chemical grafting and other modification methods. Four surface modification methods were used to modify the chopped basalt fiber surface such as acid etching, acid etching + chemical grafting, activation treatment, activation + chemical grafting. The tensile experiment, friction experiment and electrochemical experiment were conducted to study the hardness, friction and wear properties and corrosion protection properties of epoxy composite coatings. The results showed that the four surface modification methods improved the surface activity of chopped basalt fibers. The data of scanning electron microscopy showed that the change of morphology and increase of roughness were beneficial to the adhesion of fiber/coating interfaces. The data of Fourier transform infrared spectroscopy confirmed the increase of active functional groups —OH and Si—O—Si on the surface of modified chopped basalt fibers. The increase of active functional groups resulted in the improvement of the compatibility and interfacial bonding strength of chopped basalt fiber and epoxy resin. Among the modification methods to the chopped basalt fiber surface, the synergistic modification by two methods (acid etching + chemical grafting or activation + chemical grafting) showed the obvious advantages over the single modification method (acid etching or activation treatment). The method of activation + chemical grafting revealed the optimized modification effect which enhanced the bonding strength of fiber/coating interface, leading to the improvement of mechanical properties, corrosion resistance and anti-aging properties of the epoxy composite coatings. Compared with the epoxy varnish coating, the friction coefficient of the composite coating was reduced by 0.113, the hardness was increased by 32.59%, and the weight loss at the same temperature (320 ℃) was reduced by 5%. The chopped basalt fiber modified by activation + chemical grafting with KH550 endowed the composite coating with the lowest water absorption and porosity after immersion for 105 days and the impedance value above 1×108 Ω.cm2 after 133 days of immersion in the solution of 3.5wt.% NaCl. In summary, the surface modification can increase the compatibility between chopped basalt fiber and epoxy resin, and then form a strong interaction and combination, which improve the mechanical properties, heat resistance and corrosion prevention properties of the epoxy composite coatings.