Recently, advances in creating complex oxide heterostructures in atomic scale and research on special properties appears at the interfaces between two different transition-metal oxides, have promoted a new era of materials and physics research. At the heterointerface, unexpected properties could be detected which does not exist in the bulk. Two-dimensional electron gas (2DEG) at the oxide heterointerface between two insulating dielectric perovskite oxides, LaAlO3 and SrTiO3, has attracted tremendous attention with the metallic conductivity at the interface since its discovery in 2004. Intensive experimental and theoretical studies have showed that 2DEG at the oxide heterointerface exhibits a vast diversity of novel properties including superconductivity, ferromagnetism, and field induced metal insulator phase transitions. In this review, the origin and important factors of 2DEG at the oxide heterointerface and the way to manipulate this interfacial system will be discussed. (C) 2017 Elsevier B.V. All rights reserved.