Abstract: The urban development makes the surrounding environment more and more complex, and a lot of people pay their attention to protect the existing underground structures. However, the existence of the existing underground structures changes the displacement field. Therefore, the excavation process should be highlighted, and it is of great significance to correctly understand the sheltering effect of underground buildings on displacement field for determining the protection class of foundation pits for their supporting design and for protecting the safety of nearby metro stations and the surrounding buildings during the construction. Combining the sensitivity theory with the mechanism analysis, it is found that the sheltering effect is the most obvious when the spacing between the underground buildings and the retaining wall of foundation pits is 0.5H, and it can be ignored when the distance is more than 2H.