Using the portable ultrasonic feature imaging testing system of full wave acquisition of test signal,can be realize through the extraction and reconstruction of defect feature signal, automatic identification of defects,which can be applied to the surface and irregular surface detection with quantitative accuracy of 0.1 mm. The experimental results show that the low-frequency narrowband ultrasonic transducer can reduce the copper net on the acoustic attenuation and distortion, ultrasonic feature imaging tomography method can identify layered surface copper net structure of CFRP foam sandwich defects effectively,accurate recognige the location of impact of defects and debonding defects and quantification. The detection method is fast, accurate, reproducible and reliable