Abstract:TiFe and TiFe2 intermetallic compounds are formed at the interface of titanium alloy and steel because of diffusion and reaction, which influence the properties of the joints significantly. The valence electron structures of TiFe and TiFe2 were studied and their bond energies were calculated based on Yu’s empirical electron theory of solids and molecules (EET). The results show that their strongest bonds are Fe-Ti bonds and FeⅡ-FeⅡ bonds, respectively, and the energies of their strongest bonds are 14.77 and 26.96 kJ/mol, respectively. TiFe2 has stronger bond nets than TiFe, which results in its better hot stability. According to their valence electron structures, TiFe and TiFe2 put up eigen-brittleness