Dielectric composites are regarded as potential energy storage materials for electric power systems and advanced electronics because of the tunable permittivity, excellent flexibility, and high electric breakdown strengths. However, for the moment, it is still a challenge to fabricate dielectric composites combining large electrical breakdown strength and high discharged energy density. Ferroelectric (K0.5Na0.5)NbO3(KNN) particles are fabricated by solid-state reaction and introduced into poly(vinylidene fluoride) to improve energy storage capability. Particularly, the properties such as dielectric constant (epsilon(r)), electric displacement, breakdown strength (E-b) and discharged energy density (U-dis) are enhanced with the introduction of KNN particles. The composite containing 3 vol% KNN particles exhibits an ultrahighU(dis)of 14.70 J center dot cm(-3)at 480 kV center dot mm(-1), which is approximately three times that of pure PVDF of 4.80 J center dot cm(-3)at the applied electric field of 350 kV center dot mm(-1). This research is of critical significance for proposing a convenient and effective way to design high discharged energy storage dielectric composites for future flexible portable capacitors. Keywords: dielectric composite, (K0.5Na0.5)NbO(3)particle, breakdown strength, discharged energy density.