Abstract: 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 mult-icracks.