As an important part of project construction, the stability of the foundation pit project is related to urban safety. With the concept of an underground hub and three-dimensional transportation, some of the foundation pits present characteristics such as large-scale, long-period, and complex surrounding environments. At this time, it cannot be simply regarded as a temporary structure, and the influence of episodic disasters such as earthquakes needs to be considered. To calculate the safety under seismic conditions, the proposed static method is introduced into the stability analysis of the foundation pit. The proposed static method in the existing codes is summarized, and the principles of discount and amplification coefficients are discussed based on the characteristics of each code. The method is verified in terms of shear force, bending moment, and displacement using time course analysis. The results show that the characteristics of the foundation pit project should be considered when applying the proposed static method. Different from slope engineering, the acceleration of foundation pit engineering is less than or close to the surface design earthquake. Therefore, the acceleration amplification factor can be taken as 1. When the discount factor is taken as 0.25, the calculation result of the proposed static method is slightly larger than that of the time analysis method, which can achieve the purpose of envelope design.