Abstract: In this study, continuous carbon fiber-reinforced poly-ether-ether-ketone composite (CCF/PEEK) with filament pre-impregnation (prepreg) treatment was investigated. Employing synchrotron radiation computed tomography (μCT) characterization, the failure modes and mechanisms at the fiber/resin interface and interlayers during tensile/bending processes were analyzed. Combined with defect and tensile mechanical property analyses, the impact of prepreg on the structure and mechanical properties of CCF/PEEK materials was elucidated. The results revealed that due to inadequate impregnation and interlayer temperature gradients, defects existed at both the fiber/resin interface and interlayers in the prepreg sample, evolving into interlaminar cracks under tensile/bending loads, while fiber debonding and pull-out occurred in the original sample. After prepreg treatment, the average tensile strength of the samples increased by 17.21%, and the porosity decreased by 56.6%. The resin fully infiltrated the fiber bundles, significantly enhancing the fiber/resin interface bonding and mechanical properties of the material.