Dielectric composites play a crucial role in energy storage devices as they can provide high dielectric strength and energy storage density through the design of their chemical components or structure. In this work, dielectric composites with a laminated structure are proposed, and their effective dielectric permittivity and breakdown strength are calculated using the finite element method and phase-field model, respectively. The results show that the dielectric properties of these laminated structural composites are significantly affected by the difference in the permittivity and thickness ratio between adjacent layers. When the permittivity and thickness of the second layer are sufficiently small, a dramatic increase in the dielectric breakdown strength is found, which can significantly improve the energy storage performance of these dielectric composites.