Abstract: In order to research the energy -efficient design of department stores in Chongqing in depth, on the basic ofprophase investigation, anelementary model of department store is set up, and it ismade out four energy -efficient schemesinallusion to exterior wall conformation design by improving heat preservation and insulation, which are respectively comparedwith the actual designof exterior walls. By analyzing the thermal and economic indexes, find out the most effective project,which provides reference to the energy -efficient design of exterior walls of department stores, and offers a feasible method toarchitectural designer dealing with the research on energy -efficient design of a public building.