The　effect　of　sodium　tungstate　in　insulation　coating　solution　of　grain-oriented　silicon　steel　on　the　microstructure　and　properties　of　the　prepared　phosphate　insulation　coating　was　investigated　by　using　scanning　electron　microscopy　(SEM),　Epstein　square,insulating　resistance　tester　and　Fourier　transform　infrared　spectrum　(FTIR)　et　al.　The　results　show　that,　with　the　gradually　increasing　content　of　sodium　tungstate　in　the　coating　solution,　the　wetting　angle　between　the　coating　solution　and　the　grain-oriented　silicon　steel　substrate　first　decreases　and　then　increases;　the　interlamination　resistance,　lamination　factor　and　magnetism　induction　intensity　of　grain-oriented　silicon　steel　first　increase　and　then　decrease,　the　iron　loss　first　decreases　and　then　increases.　When　the　sodium　tungstate　content　is　2.0%(mass　fraction),　the　coating　solution　shows　the　best　wettability　on　the　grain-oriented　silicon　steel　substrate,　the　wetting　angle　is　39.3°;　at　the　same　time,　the　formed　insulation　coating　is　dense　and　smooth,　there　is　a　diffusion　area　about　0.8μm　at　the　junction　between　the　insulation　coating　and　the　magnesium　silicate　bottom　layer,　furthermore,　the　humidity　resistance　of　the　insulation　coating　is　not　significantly　changed;　the　interlamination　resistance,　lamination　factor,　magnetism　induction　intensity　and　iron　loss　of　grain-oriented　silicon　steel　reach　the　optimal　values,　which　are　14073Ω•mm2,　97.0%,　1.893T　and　1.051W•kg-1,　respectively.　©　2018,　Journal　of　Materials　Engineering.　All　right　reserved.