The structural design of molten salt storage tanks is of paramount importance in solar thermal power plants as it directly impacts their safe, stable, and efficient continuous power generation. This study is based on an engineering project within a solar thermal power plant located in Qinghai Province, China. It conducts a comprehensive analysis and research on high-temperature molten salt storage tanks. Using finite element software ABAQUS, shell element models and axisymmetric solid element models are established to conduct thermal coupling analysis on various aspects: the stability of the grid shell structure atop the storage tank, the integrity of the shell-to-bottom weld within the tank structure, as well as the tank wall plate and tank bottom plate. The research findings indicate that stress on the tank wall exhibits a characteristic pattern of oscillatory decrease from bottom to top, with stress concentration mainly occurring at the shell-to-bottom weld. Stress assessment conducted in accordance with ASME regulations confirms compliance with requirements. Moreover, it is observed that the friction coefficient does not directly impact the static stress of the storage tank. Instead, its significance lies in its effect on the expansion caused by high temperature, thus influencing the tank structure. Under thermal coupling effects, the friction coefficient significantly alters the stress distribution of the first-layer wall panel and the shell-to-bottom weld area. As the friction coefficient increases, the constraint effect of the foundation on the transverse expansion deformation of the bottom plate intensifies, leading to detachment of the shell-to-bottom weld from the foundation’s top surface, with detachment height continuously increasing.