Abstract: In this paper, the frequency-wavenumber (F-W) domain imaging algorithm is used to detect circular perforation defects in thin aluminum plate. A simulation model of multi-element linear array is established by PZFlex software, and the Lamb wave excited in a thin aluminum plate is used for simulating the full matrix capture function of ultrasonic phased array. In the experiment, the ultrasonic phased array instrument of M2M Company is used to capture the full matrix data of the thin aluminum plate with perforation defects. Based on the full matrix data, the F-W domain imaging method is used to reconstruct the defect damage in the self-transmitting and self-receiving mode. The 3D Fourier transform is performed on the full matrix data, and all the information of the array is used to complete the damage reconstruction. Experimental results show that the F-W domain imaging method can accurately characterize the size and shape of the circular damage, and has a good detection effect for a single defect and double defects of different sizes and distances. Compared with the total focusing method (TFM), the F-W domain imaging method has higher resolution.