Abstract: Interlaminar property is an important indicator to evaluate the overall quality of composite components. In the process of automated fiber placement (AFP) in-situ consolidation, the interlaminar properties of the composites are affected by the processes such as temperature history, polymer degradation, crystallization, interlaminar bonding, and void content. Interlaminar bonding is the primary factor of forming the overall structure between layers of the components. It is usually difficult to form perfect interlaminar bonding due to the short dwell time of temperature and pressure caused by the fast processing speed. In this study, the mechanism of interlaminar bonding during AFP in situ consolidation for high performance carbon fiber reinforced poly-ether-ether-ketone (CF/PEEK) composites was investigated. Theoretical model prediction and experimental verification were carried out for the two main processes of interlaminar bonding: Intimate contact and polymer diffusion. The influence and mechanisms of process parameters on the interlaminar bonding during in-situ consolidation process were explored and the effect of the processing parameters on the interlaminar shear strength was also analyzed. The results indicate that the time required for polymer diffusion is much lower than that of intimate contact, thus the intimate contact is considered as the main process affecting the interlaminar bonding of CF/PEEK. In addition, for the process of intimate contact, the influence of laser temperature is the most significant, while the influence of placement speed and compaction force is comparable. Interlaminar shear strength of CF/PEEK composites reaches a maximum value of 58.5 MPa at laser temperature of 450℃ and placement speed at 100 mm/s.