Ti-6Al-4V and QAl 10-3-1.5 diffusion bonding has been carried out with Ni/Cu interlayers. The diffusion-bonded joints are evaluated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and microhardness test. Intermetallic compounds at the interface zone are detected by X-ray diffraction (XRD). Interfacial microstructure of TiNi+CuTis+α-Ti forms at the Ni/Ti-6Al-4V transition zone and Cu (ss. Ni) solid solution forms between Ni/Cu interlayers. The thickness of reaction layer (TiNi) increases with bonding time by a parabolic law: y2=K0exp(-150000/RT)t, and K0=2.9×10~7 m2/s is figured out from the experiment data. The diffusion-bonded joints have been evaluated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and microhardness test. Intermetallic compounds at the interface zone are detected by X-ray diffraction (XRD). Interfacial microstructure of TiNi + CuTis + α-Ti forms at the Ni / Ti-6Al- The thickness of reaction layer (TiNi) increases with bonding time by a parabolic law: y2 = K0exp (-150000 / RT) t, and K0 = 2.9 × 10 ~ 7 m2 / s is figured out from the experiment data .