The invention discloses sandwich structured lead-free ceramic with low dielectric loss and high energy storage density and a preparation method thereof. The preparation method comprises the followingsteps: uniformly mixing an organic solvent and an emulsifier, then adding SrTiO3 powder, a binder, a dispersant and a plasticizer, and uniformly mixing to obtain SrTiO3 tape casting slurry; preparing(1-x)SrTiO3-xBaFe0.5Nb0.5O3 casting slurry with the same tape casting method; respectively carrying out tape casting on the two tape casting slurry in the manner of tape casting to obtain two kinds oftape casting film; and carrying out superposition, pressurization, rubber discharging and sintering to obtain the sandwich-structured lead-free ceramic. The ceramic has the advantages that the preparation process is simple and the technology is mature, is suitable for industrial production, has excellent energy storage characteristics, has the discharge energy density between 1.67 and 1.90 J/cm<3> calculated based on ferroelectric hysteresis loop, the energy storage efficiency of 86% and the electric field strength of 300kV/cm or above, and can exhibit a lower dielectric loss value.