The 2021 China (Changsha) International Assembled Architecture and Engineering Technology Expo (hereinafter referred to as the Expo) was successfully held at the Changsha International Convention and Exhibition Center from October 22 to 24. The Expo is jointly hosted by the Hunan Provincial Department of Housing and Urban-Rural Development, the Changsha Municipal People's Government, and the Hunan Provincial Council for the Promotion of International Trade. It lasts for three days, with an exhibition area of 60000 square meters and over 400 exhibitors. It has a wide impact at home and abroad, fully demonstrating the new landscape of "practicing three high and four new technologies, and building a green future".