Recommendation L.green_mgm_DC describes functional requirements and framework of energy-saving management system for green data centre. Functional requirements of energy-saving management includes requirements for measuring energy consumption and environmental condition, collecting and storing data, reporting data, and conducting energy-saving. The energy-saving management system consists of following functional blocks: data collecting block; data storing block; data process and analysis block; external system interfacing block; user interface block; control block. Operational flow the energy-saving management system is also provided.