The molten salt tanks, one of the critical thermal storage devices for energy storage in concentrating solar power (CSP) systems, are conducive to the adjustment of output power and the grid connection of the CSP. Due to the high temperature and heavy weight of the molten salt, the salt tanks are faced with multiple risks, including insufficient heat storage ability and structural failure. In this paper, a comprehensive study on the design, analysis and evaluation of the cold and hot molten salt tanks for Shouhang 100MW CSP plant in Dunhuang, China is presented. Research findings could be taken as a reference for engineering practices. The materials, structures and dimensions, namely the geometric model of the two tanks, are first determined according to the data of the plant and some relevant standards. On the basis of reasonable assumptions, the physical models of the two tanks are established. Thermal and mechanical processes are simulated by COMSOL Multiphysics simultaneously. The temperature, energy loss within 11 h of thermal storage and stress and deformations under steady conditions have been calculated. Additionally, the requirements for the thermal and mechanics capabilities of the two tanks are proposed, and the designed cold and hot tanks are evaluated.