Abstract: Through a example of deep foundation pit of international R&D headquarters park in science and technology park of Nanjing new city, engineering application characteristics of super-large ring bracing system are analyzed, which diameter is more than 200 meter. The structure design, layout, vertical load-bearing structure, the force and reinforcement calculation of ring are also analyzed. The related structure node and the key technical points are summarized in the designation of super-large ring bracing system. In the site test,the displacement of excavation is small and internal force of bracing system is in the controllable range. The whole construction process is safe and reliable, and protects the surroundings nearby well. The results show that these measures achieve good implementation. It provide some suggestions for same type of deep foundation pit projects.