Abstract: High-lock bolt lap joints are widely used in aircraft composite load-carrying structures, but their failure behavior under dynamic loading has not been thoroughly investigated. This study focuses on L-shaped composite protruding-head high-lock bolt lap joints. By utilizing a high-speed hydraulic servo material testing machine (INSTRON VHS 160/100-20), dynamic tensile load and displacement data were obtained for the lap joint under three loading rates: 0.02 m/s, 0.2 m/s, and 2 m/s. The high-speed camera and CT scan were employed to record the dynamic failure process and modes of the joints. A general failure process for L-shaped composite lap joints under dynamic tension was proposed, and the variation laws of tensile load, failure modes, and energy dissipation with loading rate were analyzed. Additionally, the influence of the spacers between two L-shaped laminate on the failure process of the lap joint was examined. This research provides foundational guidance for strength design and energy absorption assessment of civil aircraft composite lap joint structures.