Abstract: The good interfacial bonding performance between steel rebars and concrete is the foundation for their collaborative work, and is crucial for the load-bearing capacity and safety of reinforced concrete structures. To study the mechanism of the nonlinear bonding failure between steel rebars and concrete, the fine finite element model for ribbed steel rebars and concrete is established by a 3D scanning approach, and the accuracy of the numerical model was verified by the comparison with the pull-out test, considering the frictional resistance and the mechanical interlocking between steel rebars and concrete as well as the surface characteristic of crescent ribs. On this basis, the bond-slip behavior and damage mechanism of the steel rebars and concrete interface were investigated, and the advantages of the method proposed were discussed. The analysis results show that the interfacial bond strength increases linearly with the concrete strength. The increase of steel diameter leads to the gradual decrease of interfacial bond strength and changes the failure mode of specimens. The numerical results agree well with the experimental observations, indicating that the numerical model established by 3D scanning can accurately simulate the bond failure behavior between rebars and concrete, and the interfacial bond failure mechanism can be revealed at the mesoscale level.