The first-principles calculations are employed to investigate the electrical properties of (001) epitaxial LaGaO3/SrTiO3 heterostructure. It is found that the interface remains metallic and the atomic displacements occur mostly in the SrTiO3 side after atomic relaxation. The interface crystal field induces the Ti t(2)g orbitals to split into the nondegenerate d(xy) and two-fold degenerate d(xz/yz) orbitals. The partly filled nondegenerate dxy orbitals are the origin of two-dimensional electron gas at the interface of LaGaO3/SrTiO3 (001). Crown Copyright (C) 2015 Published by Elsevier B.V. All rights reserved.