Some　experimental　studies　were　carried　out　to　heat　transfer　characteristics　of　separated　heat　pipes,　which　based　on　the　experiment　device　of　separated　heat　pipes　designed　by　ourselves.　The　studies　were　taken　under　the　following　conditions:　the　temperature　was　between　170°C　and　250°C　and　the　heat　current　was　between　25　kW/m2　and　50　kW/m2.　The　evaporation　and　condensation　were　composed　of　seven　30　mm　seamless　steel　pipe　with　a　steel　silk　annular　fins,　the　length　of　the　pipes　were　160　mm.　The　dimensions　of　silk　annular　fins　were　outside　diameter　45　mm,　thick　film　1　mm,　4　mm　pitch.　The　experimental　results　showed　that　the　most　optimum　filling　liquid　ratio　of　separated　heat　pipes　was　between　18%　and　38%　by　all　capacity　of　pipes.　According　to　the　results　of　the　experiments,　the　synthetical　equation　of　the　average　coefficient　of　boiling　heat　exchanging　in　evaporator　and　of　coefficient　of　heat　exchanging　Nusselt　in　condenser　was　fitted　under　the　most　optimum　filling　liquid　ratio　(24%).