In order to achieve guided wave non-contact automatic inspection, based on air-coupled ultrasonic inspection technology, the A0 mode lamb wave is used to orthogonally scan the corrosion defects of the preset 0.5mm and 1mm depth grooves in the aluminum plate to obtain the defect. Location information, using the energy of the lamb wave packet and the correlation coefficient between the lamb wave virtual time reversal reconstruction signal and the original signal as the damage index to characterize the size of the defect. Finally, based on the probabilistic damage imaging method, the full multiplication method is used to calculate the defect damage index. Fusion imaging. The imaging results show that the imaging results of the virtual time reversal algorithm are better than those of the conventional energy algorithm. The results show that the position and shape of the defect are more consistent with the actual situation, and it has a better ability to distinguish the depth of the defect.