Abstract: Some of literatures have investigated the influence on deformation of deep excavations adjacent to buildings，but most of them regarded the adjacent building as a kind of uniform load directly instead of the geometry of the building，and ignored the overload depth． Therefore，taking a typical deep excavation in Qingdao supported by pile-inner bracing structures in soil-rock mixed area as a prototype，considering geometry of the adjacent building located in one side of the excavation，the characteristics of the supporting system deformation were analyzed due to variation of the overload depth． The results showed that as the deformation for supporting system far away from the building，existence of the adjacent building was favorable and the deformation almost kept unchanged with variation of the overload depth and the overload distance from the deep excavation． For the deformation of the deep excavation near side from the building，there was a critical overload depth，and if the overload depth was less than it，existence of the building would be unfavorable; otherwise，the building was favorable． The critical depth had a decreasing tendency with reduction of the overload magnitude and increase of the overload distance from the excavation． Characteristics of the near side deformation due to variation of the distance between the building and the excavation for different overload depth were analyzed． Furthermore，mechanism of the deformation of the support system under different overload depth of adjacent buildings was also discussed．