The deformation behavior of W-Cu material during high-pressure torsion (HPT) was simulated by ABAQUS software. The distributions of stress and equivalent strain, as well as the influence of applied pressure and deformation temperature on the strain accumulation of interface layer were analyzed. The simulation results show that shear deformation is mainly occurred on copper, but has little influence on tungsten, and the strain accumulation of interface layer is the largest. The increase of deformation temperature varying from 300 ℃ to 500 ℃ and applied pressure varying from 1 GPa to 3 GPa have positive effect on the strain accumulation of interface layer, but the higher temperature and applied pressure may lead to the extrusion of copper and the failure of HPT die. At the same time, the W-Cu gradient material with noble bonding interface was obtained through 5 turns of HPT processing under 300 ℃ and 1 GPa, and the diffusion distance of tungsten and copper at the bonding interface is 1.74 μm and 2.59 μm, respectively. The experimental results show that with the increase of torsion radius, the microstructures of W and Cu were significantly refined to 32.6 μm and 0.28 μm, respectively. Also, a transition layer of Cu with grain size of about 4.8 μm can be found at the interface. The microhardness of copper increases from 79 Hv to 131 Hv, and that of tungsten at the interface increases from 347 Hv to 424 Hv, which indicates that grain refinement and defect accumulation under large deformation condition are beneficial to interface bonding and performance improvement.