Microstructure　of　the　addition　of　phenyl　isocyanate-modified　graphene　oxide　nanosheets　(iGONSs)　was　examined　using　transmission　electron　microscope　(TEM)　and　physical　adsorption　analyzer,　and　thermal　behaviors　of　the　coal-tar　pitch　with　different　iGONSs　contents　were　investigated　by　thermogravimetric　analysis　(TGA).　In　addition,　the　optical　texture　and　micro-crystal　structure　of　resultant　coke　of　the　coal-tar　pitch　with　different　iGONSs　contents　were　characterized　using　reflected　polarized　light　microscopy　and　X-ray　diffraction　(XRD),　respectively.　The　results　show　that　with　the　addition　of　iGONSs,　the　thermal　stability　of　coal-tar　pitch　increases,　the　weight　loss　temperature　and　coke　value　are　improved.　The　addition　of　iGONSs　plays　a　role　in　both　the　nucleation　and　the　growth　inhibition　of　carbonaceous　mesophase,　leading　to　a　decrease　in　the　anisotropic　domain　size　of　resultant　cokes.　With　the　increase　in　the　amount　of　iGONSs,　the　interlayer　spacing　of　the　coke　increases,　while　its　average　crystallite　height　and　average　crystallite　width　decrease.