Abstract: To improve the imaging capability of small defects in plates, a time reversal operator decomposition algorithm was introduced for inspection and imaging of small damages in the plate based on guided wave. The proposed algorithm could focus wave energy on multiple tiny scatterers. Each scatterer corresponded to a significant eigenvalue, therefore, the time reversal incited signals could be obtained by the feature vector based on singular value decomposition. Then, the detection signals obtained by back propagation could be used for each scatterer imaging and to provide relevant information. The simulation results show that this algorithm can realize the defect location, and the small defect imaging resolution is significantly better than the traditional time reversal imaging method. This small defect detection method is expected to be further used in the composite board in imaging studies.