Abstract: Carbon fiber reinforced plastics (CFRPs) are widely used in national defense science and technology and have become the protective materials for main load-bearing components and some structures. Research on their fragment penetration resistance provides a basis for scientific researchers to improve the performance of CFRPs and design protective structures. To study the damage mechanism and ballistic limit velocity of CFRP target plates penetrated by fragments, numerical simulations and tests were conducted on 8g cubic steel fragments penetrating CFRP target plates with thicknesses of 5 mm, 10 mm and 15 mm, respectively. The numerical simulation of the ballistic limit velocities of the fragments penetrating CFRP target plates and the six-projectile ballistic limit velocities were obtained, and the maximum error between the numerical simulation of the ballistic limit velocity and the six-projectile ballistic limit velocity was 6.21%. A large number of different impact velocities and corresponding residual velocities were obtained by numerical simulations. Based on the THOR formula, the residual velocity model of the fragments penetrating CFRP target plates and the ballistic limit calculation formula were established. The ballistic limit formula was verified experimentally, and the six-projectile ballistic limits under different working conditions were selected and compared with the theoretical calculated values. The results show that under the same working condition, the maximum error between the test and calculated results is 4.54%.