Coal-tar　pitch　was　modified　with　rosin,　and　carbonization　behavior　of　the　modified　pitches　and　optical　texture　of　resultant　semi-cokes　were　studied　in　this　paper.　The　carbonization　behavior　was　studied　by　thermogravimetric　analysis　(TGA)　and　Fourier　transform　infrared　(FTIR)　spectroscopy　techniques,　respectively.　The　optical　texture　of　resultant　semi-cokes　was　characterized　by　polarized-light　microscopy.　The　results　show　that　there　are　marked　differences　in　the　carbonization　behavior　of　coal-tar　pitch　and　the　modified　pitches.　The　modification　results　in　a　small　decrease　in　carbonization　yield　by　1.2-3.2%　when　rosin　content　is　kept　at　5-15　wt.%　of　coal-tar　pitch.　The　modified　pitches　have　functional　groups　of　cycloparaffin,　double　bonds,　and　carboxyl　group,　which　gradually　disappear　and　aromatization　degree　increases　with　increasing　heat　treatment　temperature.　Moreover,　the　modification　contributes　to　a　notable　improvement　in　the　optical　texture　of　resultant　semi-cokes　which　varies　from　coarse-grained　mosaics　to　domains.　(C)　2009　Elsevier　B.V.　All　rights　reserved.