The　linear　and　non-linear　free　vibrations　of　a　spinning　piezoelectric　beam　are　studied　by　considering　geometric　nonlinearities　and　electromechanical　coupling　effect.　The　non-linear　differential　equations　of　the　spinning　piezoelectric　beam　governing　two　transverse　vibrations　are　derived　by　using　transformation　of　two　Euler　angles　and　the　extended　Hamilton　principle,　wherein　an　additional　piezoelectric　coupling　term　and　different　linear　terms　are　present　in　contrast　to　the　traditional　shaft　model.　Linear　frequencies　are　obtained　by　solving　the　standard　eigenvalues　of　the　linearized　system　directly,　and　the　non-linear　frequencies　and　non-linear　complex　modes　are　achieved　by　using　the　method　of　multiple　scales.　For　free　vibrations　analysis　of　a　spinning　piezoelectric　beam,　the　non-linear　modal　motions　are　investigated　as　forward　and　backward　precession　with　different　spinning　speeds.　The　responses　to　the　initial　conditions　for　this　gyroscopic　system　are　studied　and　a　beat　phenomenon　is　found,　which　are　then　validated　by　numerical　simulation.　The　influences　of　some　parameters　such　as　electrical　resistance,　rotary　inertia　and　spinning　speeds　to　the　non-linear　dynamics　of　a　spinning　piezoelectric　beam　are　investigated.