Abstract: Three-dimensional FEM models were used to simulate the Z-pin/stitching reinforced T-joint specimens. The interface failure was simulated with cohesive zone model, and the effect of Z-pin/stitching was simulated with nonlinear springs inserted into the interface. The mechanical properties of the spring, i.e. bridging law, were obtained based on a micromechanical approach. Comparing with experimental results and the FEM results, it is difficult to increase the shear carrying capacity of T-joints through Z-pin/stitching as the shear carrying capacity of unreinforced T-joint is quite high already. After analyzing the a few schemes which can increase the shear carrying capacity of T-joints, choosing stitch with high tensile strength and low tensile modulus was suggested to be used for the design of interface reinforcement.