Abstract: In the complex scenario of secondary excavation support where the main structure has already been completed and requires further excavation and transformation, the focus of this study is to safely and economically achieve the conversion of building functions based on existing geotechnical and structural conditions.Taking the People's Square in Kuala Lumpur, Malaysia as an example, the design ideas and concepts were elaborated, and an overall analysis was conducted using MIDAS GTS NX finite element software.The construction organization sequence was demonstrated in detail, as well as how to overcome technical difficulties encountered, providing solutions for similar projects.To fully utilize the existing structural system to solve support problems, it is necessary to fully cooperate with the structure and soil, and consider the overall design and construction.Itis reasonable and effective to use the original structural system as a part of the support, which is an efficient and intensive new form of deep foundation pit support.