In order to study the influence of overlying load on the internal deformation of soil outside the foundation pit, a transparent soil test chamber with controllable deformation mode of retaining structure was designed and combined with particle image velocimetry technology to analyze the influence of different deformation modes of retaining structure and overlying load on the internal deformation of soil. The reliability of the test results is verified by comparing the data obtained from the transparent soil test with the prediction curve and the engineering example. The results show that the overlying load has a significant effect on the displacement field of the soil outside the pit. Increasing the overlying load or reducing the distance between the overlying load and the retaining structure will make the influence area of soil displacement outside the pit expand to the deep soil layer, and the maximum vertical settlement and horizontal displacement will also increase. The soil depth of the soil outside the cantilever type and the convex type is significantly affected by the overlying load pressure and distance. The displacement of the upper soil is significantly affected by changing the pressure and distance of the overlying load in the cantilever deformation mode, but the displacement of the middle and lower soil is more significantly affected by changing the pressure and distance of the overlying load in the convex deformation mode. Compared with reducing the distance of the overlying load in the same proportion, increasing the overlying load has a greater impact on the displacement. It can be seen that in the actual project, it is necessary to combine the local building distribution with the underground engineering environment, and take appropriate measures to avoid the most unfavorable deformation mode of the retaining structure.