The　yellow　lasers　are　of　great　importance　as　they　have　potential　applications　in　the　areas　such　as　medical　aestheticsatomic　cooling　and　trappingand　radar.　Dy3+　is　the　best　activating　ion　for　yellow　lasers　due　to　its　4F9/2→6H13/2　radiative　transitionbut　its　spin-forbidden　transition　in　the　visible　wavelength　leads　to　a　small　absorption　and　emission　cross　sectionwhich　causes　difficulties　in　yellow　laser　output.　In　this　paperDy3+Sr3GdBO33　abbreviation　Dy3+SGBDy3+/Tb3+SGB　and　Dy3+/Eu3+SGB　crystals　were　successfully　grown　by　the　Czochralski　methodand　their　spectral　properties　and　energy　transfer　mechanisms　were　analyzed　by　room-temperature　polarization　absorption　spectraemission　spectrafluorescence　decay　curves　and　Judd-Ofelt　theoretical　calculations.　It　is　shown　that　the　co-dopant　of　Tb3+　and　Eu3+　increases　the　emission　cross　section　and　fluorescence　quantum　efficiency　of　Dy3+　in　the　yellow　emission　bandwhich　is　favorable　to　the　yellow　laser　output　of　Dy3+.　In　additionit　is　demonstrated　that　a　mutual　energy　transfer　process　between　Dy3+　and　Tb3+　occurs　in　Dy3+/Tb3+SGB　crystals　and　only　Dy3+→Eu3+　in　Dy3+/Eu3+SGB　crystals.　©　2022　Chines　Academy　of　Sciences.　All　rights　reserved.