Energy and water have become major constraints for China's sustainable development. Effective measures focused on resource conservation are important to this country. In this study, a comprehensive assessment is conducted of the energy and water use of different sectors using exhaustive data collection and an environmentally extended input-output model. Given the interdependent relationship between energy and water, this paper also identifies the key sectors with most closed energy-water nexus. The results show the following; (1) the key sectors for high direct energy consumption and water use include Mining and Washing of Coal, Manufacture of Chemicals, Manufacture of Nonmetallic Mineral Products, Manufacture and Processing of Metals, and Electricity. (2) The key sectors for high indirect energy consumption and water use include the Manufacture of Chemicals, Manufacture of Electrical Machinery, and Construction. (3) The Manufacture of Chemicals sector should be focused on due to its direct and indirect influences. A focus on the key sectors may provide a greater opportunity for simultaneously achieving energy savings and water conservation, whereas different priorities should be applied; production-based or technology-related measures are effective for influencing direct energy consumption and water use, whereas consumption-based or end-use measures are better suited for influencing indirect energy consumption and water use.