The inevitable electrothermal coupling among capacitors in a bank will lead to nonnegligible errors to the temperature as well as the lifetime prediction of the individual capacitor. In this article, the analytical thermal models with the corresponding design for capacitor banks are proposed considering the thermal coupling effect. First, a measurement-based lump thermal model and a physical-model-based analytical thermal model are proposed. Then, with the help of the proposed thermal models, the design method for the thermal matching of capacitors in a bank is proposed by optimizing the parameters of individual capacitors, such as the rated parameters and actual loading. To validate the accuracy of the proposed design, case studies based on a capacitor bank with nine capacitors are presented.