X-ray computed tomography (XCT) reconstruction technique, finite element method (FEM) and pore scale modelling (PSM) were employed to investigate the displacement distribution and its effects on transport properties of vanadium redox flow battery (VRFB) carbon felt under compression at pore-scale. Contact, friction, extrusion and bending were considered between carbon fibers. Micro-structure of a carbon felt was reconstructed by XCT first, then the displacement distribution of the microstructure in 3D (X, Y and Z direction) with different compression ratio (CR) were investigated, and last the relationship between the displacement and transport properties was quanlificated. The results show that the carbon fibers’ displacement in the Z direction (through plane) under compression is more noticeable. As CR was increased to 30%, the displacement change in Z direction is -59~+5μm, and in XY directions (in-plane) is -25~+ 16μm, the diffusion coefficient of the vanadium ion in XY direction is decreased by 15.4%, and in Z direction is decreased by 24.2%. The conductivity in XY direction is increased by 102.1%, and in Z direction increases by 46.2%. As CR is increased from 20% to 30%, the diffusion coefficient and the conductivity change faster.