Aircraft honeycomb sandwich composite panel has the characteristics of complex structure, large size and many types of defects, and the conventional ultrasonic nondestructive testing technology has the problems of low efficiency and poor accuracy. In the study, nonlinear ultrasonic Lamb wave imaging technology for honeycomb sandwich composites is proposed, which combines the advantages of large range propagation of Lamb waves and strong sensitivity of nonlinear response of defects to improve the non-destructive testing ability of honeycomb sandwich composites. Firstly, the propagation characteristics of Lamb waves in the panel are analyzed, and the probe arrangement method is designed and the defect factor is defined based on the anisotropic characteristics of wave propagation. Secondly, the imaging algorithm is designed and optimized to improve the nonlinear Lamb wave imaging effect of the defects in the honeycomb sandwich composite panel. Finally, the ability of nonlinear Lamb wave detection image to display the defects in the panel is analyzed by referring to the air-coupled C-scan and metallographic observation. The results indicate that the nonlinear ultrasonic Lamb wave image has poor resolution compared with the air-coupled ultrasonic C-scan image, which cannot show the honeycomb details. Nevertheless, the debonding and weak bonding defect areas of honeycomb sandwich composite panel can be displayed by the nonlinear ultrasonic Lamb wave testing, and it also possesses the advantages of high efficiency and same-side transceiver probe arrangement which improves the adaptability to the detection environment. Thus, it can be used for the non-destructive detection of bonding defects of honeycomb sandwich composite panels in service.