Abstract: As the power of society development, energy resources must be utilized designedly and abstemiously to meet the requirement of sustainable development. The definition and scope of energy efficiency in buildings are introduced firstly, and the status is presented on construction scale and energy consumption. Energy consuming level in Chinese buildings is compared with that in developed countries to represent the importance and urgency of energy efficiency in buildings in China. Based on the situation analysis on exterior wall insulation, a new technique, glazed hollow bead insulation system, was proposed for heat preservation and energy saving in exterior wall. Theoretical analysis was combined with experiments in the research. The experimental results and the practice in civil engineering both showed that the insulation system had excellent energy-conservation performance. The insulation system has no harmful effect on environment, additionally, it shows better economical and social benefits than other insulation techniques, therefore it can be used widely in civil engineering.