The contribution of energy management and control information system (EMS) to energy conservation and emission reduction of iron and steel industry was expounded in this paper. According to the different management modes and system coverage of iron and steel enterprises, three basic application categories of EMS were summarized. Then, the application functions and their descriptions were studied in detail, followed by the introduction of the relationship between EMS and other information systems. Finally, the comprehensive evaluation indices and recommended standards of EMS were given. It provides a guideline for iron and steel enterprises to construct EMS, beneficial to the energy conservation and environmental protection.