The geological conditions in the loess region are complex and varied, and the applicability of existing research is limited. In order to study the influence of deep foundation pit excavation on the deformation of adjacent buildings under saturated soft loess geological conditions, this paper takes a deep foundation pit in Xi'an as an example to analyze the deformation monitoring data of buildings during construction. The results indicate that the pile anchor support system and precipitation measures can effectively ensure the safety of buildings; the settlement deformation of buildings can be divided into three stages: uniform deformation, differential deformation, and stable change, and the deformation perpendicular to the long side of the foundation pit is significant; the sealing measures between interlocking piles are effective, reducing geological losses and suppressing significant settlement of outer layers and buildings outside the foundation pit.