In order to study the influence of excavation on the internal force and deformation of retaining structures and the surrounding environment under different construction procedures, we employed Midas GTS to simulate the excavation process of deep foundation pit with different construction procedures. A deep foundation pit supported by pile-anchor was taken as case study. We also simulated the influence of unbalanced heaped load on the foundation pit during the construction of base plate, and obtained the internal force and deformation of retaining structure and the ground subsidence. Results show that the horizontal displacement of retaining structure and the ground subsidence in particular were largely affected by unreasonable construction procedure, which is unfavorable for the stability of foundation pit. With timely anchor support, the maximum bending moment of pile decreased at least 41.77% compared with that in the absence of anchor support, ground subsidence reduced by 32.75% at least; unbalanced heaped load on the foundation pit led to more than 5% difference in the maximum moment and over 10% in the horizontal displacement of left and right piles. The research result will be helpful to the design of deep foundation pit, and offers reference for the design, construction and research of similar engineering.