This　article　mainly　analyzes　the　free　vibration　characteristic　of　the　sandwich　piezoelectric　beam　under　elastic　boundary　conditions　and　thermal　environment.　According　to　the　first-order　shear　deformation　theory　and　Hamilton＇s　principle,　the　thermo-electro-elastic　coupling　equations　of　the　sandwich　piezoelectric　beam　are　obtained.　Meanwhile,　elastic　boundary　conditions　composed　of　an　array　of　springs　are　introduced,　and　the　displacement　variables　and　external　potential　energy　of　the　beam　are　expressed　as　wave　functions.　By　using　the　method　of　reverberation-ray　matrix　to　integrate　and　solve　the　governing　equations,　a　search　algorithm　based　on　golden-section　search　is　introduced　to　calculate　the　required　frequency　parameters.　A　series　of　numerical　results　are　compared　with　those　reported　in　literature　studies　and　obtained　by　simulation　software　to　verify　the　correctness　and　versatility　of　the　search　algorithm.　In　addition,　three　parametric　research　cases　are　proposed　to　investigate　the　frequency　parameters　of　sandwich　piezoelectric　beams　with　elastic　restraint　conditions,　material　parameters,　thickness　ratio,　different　temperature　rises,　and　external　electric　potential.