Abstract: The interfacial bond performance between Fiber Reinforced Polymer (FRP) bars and concrete is critical to the overall load-bearing capacity and durability of structures. To reveal the nonlinear bond failure mechanism at the FRP-concrete interface, a three-dimensional full meso-scale finite element model of pull-out specimens was established. This model comprehensively considers the surface geometry of FRP bars, the meso-structure of concrete, and the mechanical interlocking and frictional interactions between them. The model generation is based on reverse modeling and random aggregate generation algorithm that integrates Voxel Distance Field (VDF) sampling, octree-based interference detection, and parallel acceleration techniques. The effects of meso-scale parameters, specifically aggregate volume fraction and elastic modulus, on the bond failure modes, bond-slip curves, and ultimate bond strength were systematically investigated. The results indicate that the proposed model accurately characterizes the mechanical response of the interface under the confinement of heterogeneous concrete matrix, achieving higher accuracy than the simplified interfacial meso-scale models. The deviations between the simulated and experimental values of peak strength and ultimate slip are only 3.75% and 2.45%, respectively. Furthermore, increasing the aggregate volume fraction and mortar matrix strength effectively enhances the interfacial confinement effect, thereby improving both the bond strength and stiffness. The established full meso-scale model serves as an effective tool for the failure analysis of FRP-reinforced concrete structures.