Abstract: The interfacial bond performance between fiber reinforced polymer (FRP) bars and concrete is the basis for their composite action and an important guarantee for the load-bearing capacity and reliability of FRP bar concrete structures. In this study, three-dimensional refined finite element models of the FRP bar–concrete interface at the rib scale were established using parametric modeling and reverse modeling approaches. By considering the anisotropic properties of FRP bars as well as the frictional resistance and mechanical interlocking between FRP bars and concrete, the mesoscopic deformation characteristics, damage evolution, and failure modes during the pull-out process were obtained. The validity of the numerical models was verified through comparison with the results of central pull-out tests. On this basis, the influence of modeling approaches on the simulation results was further discussed. The results show that the proposed method can effectively simulate the entire bond–slip process of the FRP bar–concrete interface and capture various interfacial bond failure modes, including bar pull-out, concrete splitting, and rib peeling. The bond–slip behavior of FRP bars with helically wrapped ribs is closely related to the surface profile of the bars. Compared with the parametric modeling approach, the reverse modeling approach can more accurately represent the geometric characteristics of the ribs. The relative errors of the predicted ultimate bond strength, peak slip, and residual bond strength are 1.26%, 19.18%, and 16.49%, respectively, which are significantly lower than those obtained by the parametric modeling approach, namely 13.76%, 61.63%, and 54.07%. Consequently, the numerical model established by the reverse modeling approach can produce bond–slip curves that are more consistent w6ith the experimental results.