Cyanate　ester　(CE)　resin/graphene　oxide　nanocomposites　were　prepared　via　a　solution　intercalation　method.　The　structures　and　properties　of　the　nanocomposites　were　characterized　by　XRD,　SEM,　TEM　and　TGA.　In　addition,　the　mechanical　properties　of　the　nanocomposites　were　studied　using　mechanical　testing　machine.　The　results　show　that　phenyl　isocyanate-treated　graphite　oxide　undergoes　complete　exfoliation　in　DMF　after　ultrasonic　treatment　and　thus　forms　graphene　oxide.　The　addition　of　graphene　oxide　is　beneficial　to　improve　the　mechanical　properties.　When　the　graphene　oxide　is　1%　of　CE　resin,　the　tensile　strength,　flexural　strength　and　impact　strength　of　the　nanocomposites　obtained　arrive　at　82.9　MPa,　148.6　MPa　and　12.9　kJ/m2,　respectively.　Moreover,　the　nanocomposites　exhibit　better　thermal　stability　in　comparison　with　neat　CE　resin.　When　the　graphene　oxide　is　1%　of　CE　resin,　the　coking　yield　of　the　nanocomposites　obtained　reaches　45.1%　at　1000°C.