SiCp/2014Al composites were bonded with the vacuum diffusion welding technique using Ni as the interlayer metal. Ni and Al were interdiffused and there were intermetallic compounds formed in the inter transition layer, which was composed of Ni3Al//NiAl//NiAl3. The relation between the diffusion distance and the element concentration was calculated according to Fick's second law. The relations of the diffusion concentration and the diffusion welding technique parameters were calculated. SiCp / 2014Al composites were bonded with the vacuum diffusion welding technique using Ni as the interlayer metal. Ni and Al were interdiffused and there were weremetmetlic compounds formed in the inter transition layer, which was composed of Ni3Al // NiAl // NiAl3. The relation between the diffusion distance and the element concentration was calculated according to Fick's second law. The relations of the diffusion concentration and the diffusion welding technique parameters were calculated.