Foundation pit monitoring can only provide feedback regarding the deformation of the formation and envelope structure after construction, and it is difficult to predict the deformation law of a continuous underground wall in the later stage of underground grain silo support. Taking the deep foundation pit of a continuous underground wall of an underground grain silo as an example, this paper uses Abaqus software to simulate the force of the project, explores the calculation results of the planar elastic foundation beam considering the arch effect and the numerical simulation technology of the foundation pit’s support, and analyzes and compares the rationality of the model. The analysis of the deformation form of the continuous underground wall by both calculation methods is a parabolic combination. The maximum horizontal displacement of the continuous underground wall, according to the Abaqus software, is 6.23 mm, and the other calculation result is 4.7 mm; the maximum settlement on the surface is 11.34 mm, according to the Abaqus software, and the other maximum settlement is 8 mm. The simulation results show that the simulated value is basically consistent with the measured value, and the simulated value is slightly larger than the measured value because the interference conditions are idealized during simulation. The accuracy and rationality of the numerical simulation are verified, and the parameters, such as the thickness and burial depth of the continuous underground wall, can be changed to provide a reference for the support method of a deep foundation pit similar to a continuous underground wall.