A　noncontact　temperature　measurement　technique　based　on　fluorescence　variation　was　used　to　depict　the　temperature-dependent　evolution　of　phase　transition　of　a　ferroelectric　material,　that　is,　Nd3+-doped　(K0.5Na0.5)NbO3　ceramics.　The　slope　of　the　fluorescence　intensity　curve　changes　dramatically　in　the　two　temperature　regions　of　450-475　K　and　650-675　K,　which　correspond　to　orthorhombic-tetragonal　and　tetragonal-cubic　transitions　as　confirmed　by　the　temperature　dependence　of　dielectric　constant.　Furthermore,　the　small　deviations　in　delta　TO-T　and　delta　T-c　indicate　the　good　accuracy　of　this　noncontact　method.　This　work　can　guide　other　ergodic　ferroelectrics　to　describe　phase　experience　by　the　noncontact　fluorescence　method.