Abstract: In the process of design and construction,integration of permanent and temporary structures means to combine the water sealing and dropping structure、the temporary support structure with the permanent structure. It can maximize the role of the temporary structure,or minimize the waste of temporary structures. For the first time,the author puts forward the permanent and temporary combination of the underground project. Combined with the scientific research work in recent years,the author systematically sorts out the scientific attempts and technical practices in this field in China. Under the Carbon peaking and Carbon neutrality background,the author put forward that we should vigorously advocate permanent and temporary combination of the underground project,aiming to reduce the waste of materials,the impact on the surrounding environment,and speed up the construction.