In　this　study,　a　damage　detection　index,　the　wavelet　packet　energy　rate　index,　is　proposed　for　detecting　the　structure　damage.　Dynamic　signals　measured　from　experiment　beams　are　first　decomposed　into　wavelet　packet　components,　then　the　wavelet　energy　rate　index　is　computed　and　used　to　detect　location　of　damage.　Three　kinds　of　damage　locations　are　designed　to　prove　the　validity　of　energies　index　in　experiments　with　impact　excitations.　The　results　show　that　the　WPT-based　energies　rate　index　is　sensitive　to　structural　damages.