The drastic increasing demand for energy aggravates the shortage of energy state. Using green renewable energy paves a way to solve the above problem, however, how to access and control these types of intermittent energy faces more challenges. Energy Internet (or Internet of energy), differentiated from the Internet of only transferring and sharing information, has been forecasted as a typical representative of the coming industry revolution. Comparing with the Internet, energy Internet must have the ability of efficiently managing the energy lifecycle including energy production, energy transmission and distribution, and energy consumption. Its objective contains conveniently switching in and switching out, efficiently dispatching energy and dedicatedly fulfilling all consumers' demand etc. In this paper, we analyze the potential requirements of the future energy system, state the related concepts and characters of energy Internet, survey all results with respect to the information technology in energy Internet，and conclude an energy Internet infrastructure and its support technologies. In addition, we discuss the opportunities and challenges of information technology during developing the energy Internet.