This paper describes a quantitative damage identification method for CF/EP composite laminates based on Lamb waves excited by distributed PZT wafers. The fundamental symmetric mode S0 is considered to detect defects (hole) in the plate. The Morlet wavelet and the cross-correlation analysis are introduced as signal processing tools for determining the time-of-flight (ToF) of Lamb wave. Considering the difference of Lamb wave velocities in different directions in a composite plate, the relationship of Lamb wave velocity in a unidirectional fibre reinforced laminate is studied and validated experimentally and numerically. In addition, a defect identification approach is revealed based on a regular arrangement of PZT wafers. Then, on the basis of the relationship of the wave velocity and the ToF, the location of a hole is identified by proposed method. Results demonstrate that the method is feasible in quantitative diagnosis of composite structures.