The　present　paper　attempts　the　quantitative　determination　of　the　polymerisation　degree　and　mass　fraction　of　polyoxybenzoate　in　the　polyoxybenzoate　based　composite　coatings　sintered　on　1045　steel　test　blocks.　The　determinations　were　carried　out　successfully　via　the　analysis　of　p-hydroxybenzoic　acid　hydrolysed　from　polyoxybenzoate　in　a　KOH　solution　by　use　of　high　performance　liquid　chromatography.　The　polymerisation　degree　of　polyoxybenzoate　increased　with　the　reaction　time　and　temperature,　in　particular　when　catalysed.　The　maximum　polymerisation　degree　was　27.6　under　the　optimised　conditions.　The　determined　mass　fraction　of　polyoxybenzoate　in　composite　coatings　deviated　greater　than　10%　from　the　theoretical　values　either　blocked　or　not.　This　is　possibly　due　to　the　incomplete　inhibition　of　the　sublimation　of　p-acetoxybenzoic　acid,　the　precursor　of　polyoxybenzoate,　during　the　fabrication　of　polyoxybenzoate　based　composite　material.