Abstract: Reinforced concrete internal support structures are often used in deep and large foundation pits. Reinforced concrete has the characteristic of expanding with heat and contracting with cold. When an ultra-long internal support structure is adopted, temperature changes will have an adverse impact on the support structure. Taking a project in Zhuhai as an example, this paper conducts a theoretical analysis of the stress and deformation of the internal support structure caused by temperature changes through finite element simulation of the foundation pit excavation and basement construction under normal temperature, high temperature and low temperature conditions in different seasons. The results show that the temperature stress generated by the temperature rise in summer increases the axial force of the internal support; the temperature drop in winter will not cause an increase in the axial force of the internal support, but the shrinkage deformation of the internal support concrete will lead to a greater deformation of the foundation pit support structure towards the inside of the pit. Therefore, when designing the foundation pit, the adverse effects of temperature changes on the ultra-long internal support structure should be fully considered. By reasonably selecting the support structure type and implementing effective construction measures, the impact of temperature changes on ultra-long concrete components can be reduced, thereby ensuring the safety of the foundation pit project and minimizing the impact on the surrounding environment.