Abstract: The vacuum diffusion bonding process was used to weld GH4169 alloy and the effects of process parameters on the interface structure,interface bonding holes and mechanical properties of the joints were investigated.The experimental results without interlayer show that with the increase of diffusion time and diffusion pressure in the range of 950-1 150℃,both the number and size of interface bonding hole decrease and the maximum tensile strength is 658 MPa,but the discontinuous interface holes still exist.With the Cu interlayer,the solid solution layer exists on the interface and the maximum tensile strength is 745 MPa.