This paper presents three-dimensional numerical simulation of UHPFRC-NSC composite beam with Diana. An elastic-plastic fracture model is proposed to describe material properties of UHPFRC. Differing from other concrete constitutive model, this one considers strain hardening in tension because of characteristic of UHPFRC. A total strain rotating crack model is used to describe material properties of NSC. The results of relevant push-out tests are used to describe the shear force-slip relationship of shear connection between UHPFRC girder and NSC slab. The numerical investigation focuses on the evaluation of load-deflection behavior, failure mode and shear connection. The agreement of test results and numerical results indicates the reliability of model.