Abstract: In order to investigate the impact of target damage on projectile penetration performance, a series of penetration experiments were conducted on a concrete target utilising a former jet and a subsequent kinetic energy projectile. The critical factors influencing the performance of pre-damaged concrete penetrated by the projectile were analyzed. The relationship between the strength of the concrete materials in the pre-damaged concrete target was determined. Based on this, a semi-empirical model of projectile penetration of pre-damaged concrete was established by combining the aforementioned cavity expansion theory with the results of the preceding analysis. The impact of projectile and target parameters on the performance of secondary penetration of the projectile was then analyzed. The findings indicate that the impact of pre-damaged concrete on the depth of projectile penetration is contingent upon the discrepancy in crater volume and concrete damage. It can be posited that the damage to the target is the predominant influencing factor. When there is a finite-length damage zone within the concrete target and the diameter of the cavity of the target is between 0.3 and 0.5 time the diameter of the projectile, the effect is even less pronounced. When a finite-length damage zone exists within the target, the pre-damage cavity is 0.3-0.5 times the diameter of the projectile. In this instance, the gain in depth of penetration is most pronounced. In the event of penetrating damage to the target, a ratio of 0.3 between the diameter of the target tunnel and that of the projectile is observed. The difference in penetration depth between the pre-damaged target and the pre-drilled target is found to be greater, with a gradual increase in this difference as the ratio increases further. When the damage state of the target is certain, decreasing the projectile diameter or increasing the CRH of the ogive-nosed projectile is more advantageous to increase the depth of penetration.