In deep foundation pit engineering, the support form of “bored pile + internal support” is often used for foundation pit support, but the support effect of different support arrangements on the foundation pit is different. Relying on a foundation pit project in a fast-track reconstruction and expansion project in Changzhi City, ABAQUS was used to numerically simulate the whole process of excavation of different steel support layout schemes, and the influence of different internal support layout schemes on the settlement of the surface soil around the excavation of the foundation pit, the horizontal displacement of the supporting structure and the uplift of the bottom of the foundation pit were analyzed, and then the reliability of the model was verified by combining the field monitoring results. The results show that the numerical simulation results can accurately reflect the deformation law and characteristics of the foundation pit in the process of excavation and support. When the depth of the internal support arrangement is small, it has a good control effect on the maximum horizontal displacement of the supporting pile and the surface settlement outside the pit. When the depth of the internal support arrangement is large, the maximum uplift at the bottom of the pit has a certain control effect. Increasing the number of internal supports has different effects on reducing the maximum horizontal displacement of the supporting pile and the maximum uplift at the bottom of the pit.