Carbon fiber-reinforced plastics are prone to delamination defects during drilling and processing, and the delamination defects seriously affect the mechanical properties of the components, and there are serious safety hazards. For the detection of delamination defects at the hole edge of carbon fiber-reinforced plastics, a 1 / 4 matrix total focusing method based on the segmented annular arrays is proposed. Four structures of segmented annular arrays, R4×S8, R3×S12, R3×S16, and R4×S12, are designed. The characteristics of the focused sound field of each array are analyzed by numerical simulation comparisons, and the segmented annular array probe is finally determined to be the 5 MHz R4×S12 probe. By using this probe, the full-matrix capture of the upper, middle, and lower layer defects of the hole-edge delamination specimens of carbon fiber composites is performed, and the full-matrix 3D imaging and 1 / 4-matrix 3D imaging are implemented by using the VTK toolkit, respectively. The results show that the 1 / 4-matrix method has higher defect contrast than the full-matrix method for 3D imaging. The defects size characterization error of the 1 / 4-matrix method is smaller, with an error of no more than 6% . Compared with that of full-matrix imaging, the signal-to-noise ratio enhancement of the 1 / 4-matrix imaging is in the range of 3. 43~ 7. 61 dB, which effectively improves the image quality