Porous　carbons　were　prepared　by　pyrolysis　of　the　mixture　of　coal-tar　pitch　and　nano-MgO,　and　the　effect　of　carbothermal　reduction　between　nano-MgO　and　carbons　on　their　microstructures　was　studied.　Pyrolysis　behavior　of　the　mixture　was　characterized　by　simultaneous　thermogravimetry-differential　scanning　calorimetry　(TG-DSC)　and　X-ray　diffraction　(XRD).　In　addition,　the　microstructures　of　resulting　porous　carbons　were　studied　using　scanning　electron　microscopy　(SEM),　transmission　electron　microscopy　(TEM),　Raman　spectroscopy　and　nitrogen　adsorption-desorption　measurement.　Results　show　that　the　carbothermal　reduction　occurs　when　the　temperature　is　beyond　1300　degrees　C,　greatly　influencing　the　microstructures　of　the　resulting　porous　carbons.　With　the　increasing　of　temperature,　the　porous　carbon　prepared　possesses　a　thinner　thickness　of　pore　wall　and　a　higher　specific　surface　area　with　a　less　mesopore　volume.　When　the　temperature　arrives　at　1800　degrees　C,　the　porous　carbon　prepared　exhibits　three-dimensional　network　structures　consisting　of　few-layered　graphene　sheets.　(C)　2017　Elsevier　B.V.　All　rights　reserved.