3D meso-scale finite element models of ultra high performance fiber reinforced concrete (UHPFRC) based on in-situ micro X-ray Computed Tomography (CT) images are developed and validated in this study. The CT images of 16.9 μm voxel resolution from a progressive wedge-split test were processed and converted into meso-scale 3D tetrahedron meshes considering the spatial distribution and dimension of pores and fibres. The fibre-matrix interfaces were indirectly modelled by truss elements embedded in the matrix, with equivalent plastic constitutive laws transformed from orientation-dependent bond-slip relations. The damage and fracture of the mortar matrix were simulated by the concrete damage plasticity model. The simulated load-displacement curves, final crack pattern, and load-crack width curves were found in excellent agreement with the in-situ CT test. The image-based 3D models are proved very promising in elucidating fundamental mechanisms of complicated crack initiation and propagation of UHPFRC.