Super-hydrophobicity polyhedral oligomeric silsesquioxane-modified graphene oxide (POSS-GO) was synthesized by one-step reaction between graphene oxide (GO) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS-NH2). Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra indicated that the POSS were successfully connected to the edge and surface of GO nanosheets. Scanning probe microscope (SPM) and transmission electron microscope (TEM) images demonstrated that the POSS-GO with a thickness of 1.58 nm presented a stably dispersion in anhydrous ethanol. Results from electrochemical behaviors showed that the proper incorporation of POSS-GO could availably improve the anticorrosion ability of epoxy based coatings in simulate marine environment (3.5 wt% NaCl solution). The good dispersion of POSS-GO helped to fill the original defect and enhanced the complication of penetration path. The super-hydrophobicity of POSS-GO was beneficial to the reduction of actual contact zone. The synergistic effect of good dispersion and super-hydrophobicity promoted the enhancement of anticorrosion ability for composite coatings.