Abstract: Conducting research on the dynamic shear behavior of fiber reinforced polymer (FRP)-concrete interfacial is of great significance to the evaluation and design of the impact-resistance of FRP externally strengthened concrete members. A numerical simulation method for the dynamic shear behavior of FPR-concrete interfacial was proposed based on the concrete 3D mesoscale model and the zero-thickness cohesive elements of adhesive layer, and then it was validated through a comparison with the failure modes of bonding interface, interfacial shear stress-slip relationship and FRP strain time-histories of the dynamic single shear test and the improved notched beam impact test. The experimental phenomenon of the failure interface transferred from concrete to adhesive layer due to the strain rate hardening effect of aggregate and mortar at high loading rates was reproduced. Furthermore, the influences of volume fraction of aggregate, aggregate type and mortar strength on the interfacial dynamic shear resisitance were analyzed. It indicates that the debonding loads and the peak interfacial shear stresses increase with the increase of aggregate volume fraction and mortar strength, while the aggregate type has little effect. Through a comparison with the impact force-time histories, mid-span deflection-time histories and failure modes of impact tests on FRP-strengthened RC beams, it is shown that with the heterogeneity of concrete materials considered, the mesoscale model can more accurately simulate the FRP debonding failure, the shedding of concrete cover and the crack distribution of RC beams than that of the macroscale model, which demonstrates the applicability of this established method in the impact resistance analysis of FRP-strengthened RC beams.