Precipitation　of　Y5O4F7　nanocrystals　in　oxyfluoride　glass　is　realized　through　a　conventional　melt-quenching　process　and　subsequent　heat-treatment.　XRD　patterns,　absorption　spectra,　HR-TEM　images,　and　EDS　mapping　results　show　that　Er3+　ions　and　Yb3+　ions　co-doped　Y5O4F7　nanocrystals　are　formed　in　glass-ceramics.　Upon　980　nm　laser　excitation,　significantly　enhanced　up-conversion　emission　from　Er3+　ions　are　obtained　due　to　the　low　phonon　energy　and　low　symmetry　local　environment　provided　by　Y5O4F7　nanocrystals.　Changes　in　the　emitting　color　and　decay　curves　indicate　that　the　increase　of　Yb3+　ions　doping　concentration　leads　to　highly　efficient　energy　transfer　between　rare-earth　ions.　When　evaluating　the　potential　application　in　temperature　sensing,　the　sensitivity　decreases　from　1.51　%　K-1　to　1.21　%　K-1　at　300　K　with　the　increase　in　concentration　of　Yb3+　ions.　The　laser　heating　effect　is　observed　and　the　largest　temperature　increment　of　145.2　K　is　obtained　when　the　irradiation　power　of　laser　increases　from　100　mW　to　900　mW.　These　results　illustrate　that　the　rare-earth　ions　doped　glass-ceramics　containing　Y5O4F7　nanocrystals　are　promising　up-conversion　materials　in　applications　such　as　color　display,　temperature　sensor　and　laser　heater.