In this work, an atomistic-based finite temperature multiscale interphase finite element method has been developed, and it has been applied to study fracture process of metallic materials at finite temperature. The coupled thermomechanical finite element formulation is derived based on continuum thermodynamics principles. The mesoscale constitutive relations and thermal conduction properties of materials are enriched by atomistic information of the underneath lattice microstructure in both bulk elements and interphase cohesive zone. This is accomplished by employing the Cauchy–Born rule, harmonic approximation, and colloidal crystal approximation. A main advantage of the proposed approach is its ability to capture the thermal conduction inside the material interface. The multiscale finite element procedure is performed to simulate an engineering nickel plate specimen with weak interfaces under uni-axial stretch. The simulation results indicate that the crack propagation is slowed down by thermal expansion, and a cooling region is found in the front of crack tip. These phenomena agree with related experimental results. The effect of different loading rates on fracture is also investigated.