Abstract: The W-Fe-Ni alloy was diffusion bonded with HR2 steel using Ni as interlayer by hot isostatic pressing (HIP). The mechanical properties were evaluated by tensile tests. The microstructure of interface and the diffusion behaviors of different elements were analyzed through OM, SEM and EDS. Results show that, effective welding was obtained between W-Fe-Ni alloy and HR2 steel under the condition of 1200~1300℃, 130 MPa and holding time of 1 hour. The basemetal fractured during the tensile tests when stress raised to about 650 MPa but the interfaces still keep fine. There is no crack between W-Fe-Ni alloy and HR2 steel. Interdiffusion are sufficient through the base metal and interlayer. These elements including W, Co, Cr, Mn diffused to theopposite sides while Ni shows a tendency of diffusing to W-Fe-Ni alloy. The interface presents a good metallurgical binding.