Enhanced Geothermal System (EGS), known as Hot Dry Rock (HDR), is an engineering technology where the heat energy is extracted from low permeability and low porosity rock, namely, HDR in order to gain the quantity of energy. Although the history and development of EGS has been more than 30 years, only a small number of countries in the world have a voice in this respect, such as the United States, Britain, France, Germany, Switzerland, Japan, Australia, etc. The basic concept, research and development status, key technologies, issues and expectation involving the EGS are mainly discussed.