Abstract: With a distinct structure that is fully integrated, three-dimensional braided composites not only overcome the defects in laminated composites which have relatively poor mechanical properties in the thickness direction and are prone to interlaminar delamination, but also are superior in high strength-to-mass and stiffness-to-weight ratios, improved impact resistance and damage tolerance as compared with traditional metal materials. Owing to these merits, they also have broad potential applications in automobile, high-speed train, navigation, aviation, and aerospace industries. Plate specimens of three-dimensional four-directional braided composite(3D4DBCo) were designed and impacted at different locations by the steel ball with an approximate initial velocity of 210 m/s with the help of the air gun experiment system in this paper. On the basis of macroscopic and microscopic observation, the damage morphology and the failure mechanism of 3D4DBCo subjected to high speed impact of the steel balls were analyzed and summed up. What's more, the macro-level continuum damage mechanics (CDM) finite element model of 3D4DBCo was established, and the comparisons between numerical simulation and experiment results show highly agreement in residual velocity within 5%, as well as the damage characteristic, which validate the effectiveness of the macroscopic CDM finite element model.