The structures, electronic properties, and surface energies of low-index surfaces of L1(2)-Al3Sc intermetallic were studied systematically by the first-principles calculations based on density functional theory. The calculated results show that the relaxations are mainly localized within the outermost layer and the second layer, and charge density falls toward the vacuum region greatly. Some surfaces of L1(2)-Al3Sc exhibited significant oscillatory geometric relaxation and anti-symmetric relaxation characteristics. The calculated surface energies of stoichiometric surfaces are independent on chemical potential of Al atom, while surface energies of non-stoichiometric surfaces are correlated with the chemical potential. It is found that (1 1 1) surface and AlSc-terminated (1 0 0) surface are thermodynamically stable than other surfaces in a wide range of Al chemical potential. (C) 2013 Elsevier B.V. All rights reserved.