The existing foundation bearing capacity characteristic analysis model does not establish the boundary conditions of foundation bearing capacity, which leads to the large error between the numerical simulation results and the actual measurement. Therefore, under the influence of long-term construction, taking Beijing Daxing Substation as an example, a method for analyzing the bearing capacity characteristics of the substation foundation is designed to provide guarantees for comprehensive construction methods. The geotechnical mechanical characteristic parameters are calculated, and the correlation between geotechnical particles and surrounding stress is analyzed. It is divided into smooth surface and rough surface. The mechanical characteristics of soil on both sides of the foundation is respectively calculated, the boundary conditions of foundation bearing capacity are established through multi-point intersection. The mathematical model of substation bearing capacity is constructed, the upper limit of regional foundation bearing capacity is calculated, and the comprehensive construction method is matched. The experimental results show that the error between the numerical simulation results obtained by the experimental group and the actual values is about 11.35%.The total cost of the experimental group is 736.46 million yuan, and the construction cost of the construction method is less. The analysis of the bearing capacity characteristics of the substation foundation under the influence of long-term construction and the practical application effect of the comprehensive construction method are better.