Optical　floating　zone　(OFZ)　technique　is　one　of　the　most　used　methods　for　growth　of　single　crystals.　Although　OFZ　has　been　extensively　investigated　for　past　decades,　the　temperature　distribution　during　growth　has　not　been　understood　due　to　the　complicated　process　during　growth.　It　makes　the　optimization　of　growth　parameters　very　difficult.　In　this　work,　we　presented　a　simplified　model　to　calculate　the　temperature　field　in　floating　zone　by　FEM.　The　optical　properties　of　grown　crystal　and　ceramic　perform　rod,　lamp　power,　filament　dimensions,　ceramic　rod　diameter,　floating　zone　dimensions,　and　ambient　gas　cooling　rate　were　considered　in　the　model.　The　calculated　results　show　good　agreement　with　the　experiments.　The　developed　model　opens　up　a　new　way　to　optimize　the　growth　parameters　for　a　variety　of　single　crystals.