Local　symmetry　of　crystal　field　is　crucial　for　optical　temperature　sensitivity　that　based　on　the　thermal　couple　levels　of　rare　earth　ions.　In　this　work,　Lu3+　ions　were　introduced　to　alter　the　local　environment　of　Er3+　ions　in　oxyfluoride　glass-ceramics.　X-ray　diffraction　patterns　and　transmission　electron　microscope　images　show　that　Y5O4F7　nanocrystals　are　precipitated　in　glass-ceramics.　Incorporation　of　rare-earth　ions　into　the　Y5O4F7　nanocrystals　is　confirmed　by　absorption　and　electron　energy　loss　spectra.　The　Judd-Ofelt　(J-O)　theory　analysis　reveals　that　local　symmetry　of　the　crystal　field　around　Er3+　decreasing　due　to　Lu3+　co-doping.　Temperature　sensing　property　of　the　Y5O4F7:　Er3+/Yb3+/Lu3+　nanocrystal　incorporated　glass-ceramic　was　investigated,　and　the　optimal　relative　temperature　sensitivity　SR　reaches　1.50　%　K−1　in　0.25　mol.%　Lu3+　doped　specimen.　Results　show　that　the　moderate　addition　of　Lu3+　can　improve　the　temperature　sensitivity　of　glass-ceramic　containing　Y5O4F7:Er3+/Yb3+　nanocrystals,　which　provide　a　promising　avenue　for　optical　temperature　sensing.　©　2024　Elsevier　Ltd　and　Techna　Group　S.r.l.