Diffusion welding method of titanium or titanium alloy and stainless steel

The invention discloses a diffusion welding method of titanium or titanium alloy and stainless steel. A plate pack having the same material quality with welded workpieces is welded into a block structure in advance. The plate pack is lengthways cut into slices along the block structure to form a structural middle layer 7. The middle layer is processed and then vertically arranged between the welded workpieces for diffusion welding. Because the middle layer having the same material quality with the workpiece is adopted, a joint heterogeneous interface combination mode is changed into a combination mode that half heterogeneous workpieces are directly combined and half heterogeneous workpieces are combined, and the titanium or titanium alloy and stainless steel workpieces are in high-intensity connection. In the diffusion welding method, the tensile strength of the joint is improved to above 80% from 50-70%(week side workpiece intensity) obtained by the direct diffusion welding technology, and various types of titanium or titanium alloy and stainless steel can be in high-intensity connection.