The structural cut and convert (CC) method for largescale underground space, which has been successfully applied to underground parking lot of CREG, is put forward. The idea of CC method is expounded based on the characteristics of traditional methods. The innovations of forming process of largescale underground space, structural segment of shaped steel and reinforced concrete and nodes treatment are emphatically introduced from the aspects of cut and convert of the underground structure; the treatment of Class B nodes and the phenomenon of overallcarryingsoil of pipe jacking machine are solved. Finally, the possibility of expansion application of the CC method is discussed, and the preliminary schemes of multilayered, curved, longdistance, and prefabricated largescale underground space are introduced. The successful development of the CC method can provide a new set of solutions for the development of largescale underground space in the city.