Dielectric ceramic materials are widely used in pulse power systems, energy storage capacitors, inverters and ultrasound medical equipment due to their high power density, fast charge/discharge rate and good thermal stability. Since the demand for high-performance energy storage capacitors is rapidly growing, advanced dielectric ceramic materials are urgently needed. In this work, lead-free high-entropy ferroelectric ceramics are developed as novel dielectric materials, opening up a new window to improve the performance of energy storage capacitors. Firstly, wet chemical methods were used to prepare high-entropy perovskite (ABO₃) nano-powders, achieving a uniform mixture of multi-component metal elements with equal molar ratios and reducing the sintering temperature of the ceramics; the A-site or B-site of the ABO₃ structure was randomly occupied by 4-5 metal ions, successfully alternating the energy storage properties of high-entropy ferroelectric ceramics. Secondly, high-entropy ferroelectric films with a thickness of 200-800 nm were prepared by spin coating, which have an ultra-high breakdown electric field (>10.0 MV/cm); Through tuning the electric field endurance, saturation polarization and remnant polarization of the high-entropy ferroelectric films, the energy storage density can be increased to as high as 16.0 J/cm³. The results demonstrate that the high-entropy ferroelectric ceramics could be promising dielectrics for energy storage application.