Abstract: The effects of Cr, Mo atoms on cohesive energy and electronic structure of FeAl/Fe3Al phase interfaces were investigated by first-principle based on density functional theory. Results show that both Cr and Mo atoms preferentially substituted Al atoms on FeAl/Fe3Al phase interfaces, and cohesive energy and fracture strength of phase interfaces increased, this attributed the substitution. Adding Cr and Mo atoms increased the number of bonding peaks of FeAl/Fe3Al phase interface density of state, the form of density of state of Al and Fe atoms on FeAl/Fe3Al phase interface, and the charge density of phase interface.