The　nonlinear　vibrations　and　chaotic　dynamics　of　an　L-shape　beam　structure　are　studied　using　theoretical　and　experimental　method.　First,　the　governing　equation　is　established　and　the　perturbation　analysis　is　done　using　the　method　of　multiple　scales　to　obtain　a　class　of　four-dimensional　averaged　equation.　Based　on　the　averaged　equations,　numerical　simulations　are　presented　to　analyze　the　nonlinear　responses　and　chaotic　dynamics　of　the　L-shape　beam　structure.　Finally,　the　nonlinear　vibrations　of　the　L-shape　beam　structure　are　studied　by　experimental　method　and　periodic　motions　and　chaotic　motions　are　found　from　the　experimental　solutions.