As a traditional dielectric capacitor material, barium titanate (BaTiO3) ceramics have strong ferroelectric property, which leads to low energy storage density. However, the relaxation ferroelectric can be obtained through doping to weaken the ferroelectric property and improve the energy storage performance. In this paper, BaTiO3-based ceramics modified by BiScO3 and (Sr0.7Bi0.2)TiO3, a ternary ceramic material (0.99-x)Ba(Zr0.1Ti0.9)O3-x(Sr0.7Bi0.2)TiO3-0.01BiScO3(abbreviated as BZT-xSBT-BS) was designed, owing to the enhanced relaxation properties induced by bismuth series compounds. The phase structure of BZT-xSBT-BS ceramics prepared by traditional solid-state method is not changed due to doping, and they are pure cubic perovskite structure at room temperature. Dielectric and ferroelectric tests and analysis show that BZT-xSBT-BS ceramics have typical relaxor ferroelectric properties. Sr2+ and Bi3+ ions substitutions produce thermionic relaxation polarization, which contributes to the polarization and increases the dielectric constant of BZT-xSBT-BS ceramics, but the dielectric loss will increase due to its slow response speed. An appropriate amount of (Sr0.7Bi0.2)TiO3 can improve the dielectric, ferroelectric, strain and energy storage properties of BZT-xSBT-BS ceramics. BZT-xSBT-BS ceramics with x=0.015 show excellent properties, εr~10 372, tanδ~0.019, Pmax=16.42 μC/cm2, Ec=1.41 kV/cm, S+max=0.12% (@40 kV/cm), WD=0.181 J/cm3, η=79.4% (@60 kV/cm).