This paper is intended to design and prepare a radome protective coating with integrated excellent wave transmission and corrosion resistance. Firstly, silane coupling agents of 3-aminopropyl triethoxysilane (KH550) and γ-(2,3- epoxypropoxy) propyltrimethoxysilane (KH-560) were used to modify graphene oxide(GO) and silicon nitride(Si3N4) to prepare f-GO and f-Si3N4, respectively. Then, f-GO and f-Si3N4 were combined by covalent bond due to the reaction between the epoxy group and amino group in the modified KH560 and KH550, respectively. Five kinds of f-GO/f-Si3N4 composite materials were prepared by regulating the contents of f-GO in the composite materials. After that, the f-GO/f-Si3N4 composite materials with mass fraction of 5wt.% were added into the epoxy based composite coatings which were used as nanofiller. The dispersion states of the f-GO/f-Si3N4 composite materials were studied by SEM images of coating surface and fracture surface. The anticorrosion performances of the composite coatings were estimated by polarization curves, electrochemical impedances and water absorption. Moreover, the wave transmission performances of the coatings were measured by dielectric constant and dielectric loss tangent. The properties and structure of f-GO and f-Si3N4 were confirmed by FT-IR spectra, XPS spectra, TEM images, and TG curves. The results also showed that the dispersion of the f-GO/f-Si3N4 composite materials increased at first and then decreased as the content of f-GO in above composite materials increasing. From the polarization curves, the epoxy coating modified by GS-15 obtained the minimum corrosion current density (1.62×10–11 A/cm2) and much more positive corrosion potential (–0.462 V) among the title coating compositions. Electrochemical impedance spectroscopy showed that the |Z|0.01 Hz of the GS-15 modified epoxy coating after 3000 h immersion was 9.2×1010 Ω cm2, which was two orders of magnitude higher than the low frequency impedance of GS-0 modified epoxy coating. The GS-15 modified epoxy coating also showed the lowest water absorption. The dielectric properties of the coatings could also indicate that GS-15 modified epoxy coating had higher dielectric stability and the lowest dielectric constant and dielectric loss. According to the above results, the f-GO/f-Si3N4 modified epoxy coating has the best corrosion resistance and wave transmission performance, when the ratio of f-Si3N4 to f-GO is 7 to 3 with 5wt.% addition of the composite nanofiller in the composite coatings.