In March, “ISO 50021 general guidelines for selecting energy savings evaluators”, developed by the Resources and Environment Branch of China Institute of Standardization, was officially issued by the International Organization for Standardization. The ISO/TC 301 Technical Committee on Energy Management and Economics is responsible for this standard. Energy-saving evaluation is one of the key technologies in energy-saving work. ISO/TC301 has formulated and issued a number of energy-saving calculation and evaluation standards at the national level, organizational level, project level and so on. However, the inadequate capacity of energy-saving assessors and institutions has affected the credibility of the assessment results, and has become one of the important obstacles for countries to implement energy-saving policies and promote energy-saving technologies. ISO 50021 standard stipulates the basic principles and related responsibilities for selecting energy-saving assessment personnel, and puts forward personnel capacity requirements as well as key knowledge and skills. The issuance and implementation of the standards is expected to help to enhance the key capabilities of energy conservation assessors, guide users to select qualified energy conservation assessors or institutions, and promote the extensive development of new market-oriented energy conservation mechanisms such as energy management contracts, voluntary energy conservation agreements, energy conservation trading, energy efficiency financing, etc.