With the characteristics of large space span, complex building function and structure, the underground parking lot is usually constructed by opencut method, while in central urban area, opencut method is difficult to be carried out due to environmental constraints, and the traditional underground excavation methods are considered to be difficult, risky and inefficient. Hence, as a new construction method of underground space, the structural cut and convert (CC) method is proposed. The method divides the largescale underground space structure into small units, and then converts the whole structure into permanent structural system after the implementation of mechanized excavation of each part, and finally forms a large crosssection underground space. The application of the method to the underground parking lot construction can effectively reduce the influences of construction on ground environment, and the whole construction process is safe and fast. How to combine the structural design of underground parking lot with construction method to achieve rational design and safe, convenient and costeffective construction is the primary issue for the application of the method. A case study is made about the CC method, and some suggestions are put forward so as to provide references for similar projects in the future.