In order to summarize the design and practical experience of deep and large foundation pits under complex conditions, the Nanjing Global Trade Plaza project is taken as an example to introduce the implementation plan for synchronous construction of adjacent ultra-large and ultra-deep foundation pits under soft soil and water-rich stratum. The technical measures taken to achieve synchronous construction and protect rail transit are detailed, and the implementation results are analyzed. Practice has shown that the design plan and the targeted technical measures taken have effectively solved the problem of synchronous implementation of adjacent super-large and super-deep projects, and ensured the safety of adjacent rail transit facilities. The results can provide references for design and construction of deep foundation pit engineering with similar conditions.