We employ density functional theory to investigate TiAl3/Al interfaces with the orientation of (001) Al//(001)TiAl3 by electronic structures, relaxed atomic geometries and adhesions. The preferable interfacial atomic structure is that wherein Al atoms continue on the natural stacking sequence of bulk TiAl3. Two types of TiAl3 (001) slabs, Ti-centered, all Al atoms, are adopted to compare interfacial energy, interfacial electronic structure. The calculated adhesion energies Wad of the two types of interface are very close, and are quantitatively in agreement with other calculated results of Al on the carbide and nitride, but much lower than the (111)Al[1 0]Al//(0001)TiB2[11 0]TiB2 adhesion energy. We have thoroughly characterized the electronic structure and determined that the metallic Al-3p and Ti-3d bonding constitute the primary interfacial bonding interaction.