Acrylic resin was reinforced with micro/nano SiO2 particles before and after being chemically modified by KH550.The chemical compositions of the resin before and after being cured were characterized with an intelligent Fourier transform infrared spectroscopy(FTIR).Various kinds of Acrylic resinSiO2 composite coatings were prepared on cast iron surface with a bar coater.Friction coefficient,wear rate and wear morphologies of the coatings were evaluated with Rtec tribology tester,surface profiler and SEM,respectively.The results show that the modified SiO2 particles can remarkably enhance the tribological performance of the coating better than unmodified SiO2.Modified nano SiO2 particles can improve the wear resistance of acrylic resin in dry condition,but less effect in sea water.Modified micro SiO2 particles can improve the antiwear performances of the composite coatings but show no obvious influence on their friction coefficients.The hybrid coatings containing both of modified mirco SiO2 and nano SiO2 particles display better antiwear ability in dry condition,but worse than that the coating containing only single SiO2 particles in sea water. 