This paper presents a numerical investigation of fracture behaviors of concrete-steel interface under wedge splitting. The consideration of heterogeneity for the materials is achieved by assigning the elements random strength and elastic modulus by assuming a Weibull’s distribution. The fracture pattern transits from the predominated adhesive layer fracture to the dominated concrete cracking as the interface cohesive strength changes from lower than concrete tensile strength to higher than that. Local cracks can also occur duo the heterogeneous assumption. The numerical results and have an agreement with the experimental results.