Strain　mode　is　sensitivity　to　structure　local　characteristics　change.　It　is　adopt　as　response　signal　to　Coiflet　continuous　wavelet　transform　to　crack　location　and　extent　detection　for　simple　beam　structure.　Damage　location　is　identified　by　modulus　maximum　of　continuous　wavelet　transform.　The　relationship　between　Lipschitz　exponent　and　damage　extent　is　built　and　the　influence　of　multi-cracks　detection　is　also　studied.　Numerical　simulation　show　the　method　of　damage　detection　based　continuous　wavelet　transform　can　realize　damage　location,　and　with　the　damage　extent　increase,　the　Lipschitz　exponent　decrease　for　single　crack　and　multi-cracks.