With the rise of ultra-high performance concrete (UHPC), researches show that UHPC as connection elements in components can improve the performance of the overall structures. The bond strength of the joint interface has drawn increasing attention worldwide. However, there is limited information on the effect model of the interfacial properties between UHPC and normal concrete. In present study, by summarizing existing experimental results and comparing experimental methods on the basis of extensive literature research, three interfacial cohesion values with different roughness were obtained (i.e. 2.24 MPa, 2.37 MPa and 2.66 MPa), with friction coefficient of 1.42, 1.63 and 1.64, respectively. The friction coefficient calculated by direct tension test was generally larger than that obtained by splitting or bending test. The formula of UHPC-NC interface bonding strength based on cohesion and shear strength was proposed. Based on traction-separation model, a 3D finite element model suitable for tensile-dominated components and compressed-shear-dominated components was established. The cohesion and contact damage parameters suitable for smooth, medium rough and rough interface were proposed. Several finite element models of the experiments in past literature were established to verify the validity of the proposed traction-separation parameters. The finite element calculation and experimental results were well fitted, which can provide reference for later FEM study.