The core value goal of energy reform in China is to improve energy system efficiency in all aspects. The connotation of energy system efficiency in the new era of energy reform is explained from six aspects such as energy economic efficiency, energy technical efficiency, energy carbon.free efficiency, energy harmless efficiency, energy security rate and energy intelligence rate. It is analyzed and pointed out that developing comprehensive energy service is the strategic pathway to promote energy system efficiency. Further more, the market opportunities of comprehensive energy service in the near and medium terms are explored emphatically.