Two‐dimensional (2D) nanofillers can effectively improve the performance of nano‐dielectrics by having larger aspect ratios and larger electron‐scattering interfaces than one‐dimensional (1D) nanofillers and zero‐dimensional (0D) nanofillers; the formation of a large interfacial area in the polymer matrix effectively traps or scatters the mobile charges and increases the curvature of the propagation paths of the electric tree, thus effectively increasing the breakdown strength and the energy‐storage density of nanodielectrics. In this article, the intrinsic mechanism of 2D nanodielectrics is elaborated using percolation theory, microcapacitance theory, interfacial model, and ping‐pong racket model. Surface modification, oriented alignment, and multilayer structural design are reviewed to enhance the dielectric properties of nanodielectrics. Additionally, an outlook on the multiple challenges and potential opportunities in the process of preparing energy‐storage capacitors with excellent performance is provided.