Abstract: This paper presents finite element(FE) model study on reinforcing in through-thickness direction of composite T-joint with z-pin based experiment of z-pin bridging law. Function of z-pin contain two aspects, i. e. z-direction and x-direction resistance of composite delamination. In the model, z-direction and x-direction resistance based z-pin are modeled by z-direction and x-direction nonlinear-spring that link a pair nodes.So, the curves of force-displacement gained by experiments of mode Ⅰand mode Ⅱ z-pin bridging laws were endued to all nonlinear-springs to simulate z-pinned composite T-joint interlaminar performance. The effects of different z-pin spacing and span on the force of pulling off were examined. The results show that the displacement and the maximal force of pulling out is greatly dependent on span and z-pin spacing, respectively.