Energy internet is an important infrastructure for large-scale distributed renewable energy access and energy sharing in the future. Considering the fundamental goal of energy internet construction, the characteristics of energy internet are presented, and an energy internet structure based on energy router is proposed. An energy router with hierarchical function modules is proposed, which is capable of supporting the access of distributed sources, electric vehicles, and loads. The detailed introduction of the function modules are presented. A modularized main circuit with multiple power interfaces of the energy router is also proposed. An energy trading mode based on the energy router is proposed, which can not only realize the free and fair energy trade, but also realize the local or nearest consumption of the distributed energy automatically. The energy trading process is also presented.