The invention discloses a giant dielectric low-loss barium strontium titanate ceramic. The chemical formula of the ceramic is Ba1-xSrxTiO3, wherein x is a mole number of Sr, and the range of x is thatx is more than or equal to 0 and less than or equal to 0.3. In addition, the invention also discloses a preparation method of the barium strontium titanate ceramic. The barium strontium titanate ceramic prepared by the method provided by the invention improves the dielectric constant of a barium titanate ceramic product, simultaneously reduces the loss of the barium titanate ceramic product, realizes a breakthrough of a barium titanate ceramic system, effectively improves the energy storage density and comprehensive performance of the barium titanate ceramic product, expands the application field of the barium strontium titanate ceramic product as a high-voltage energy storage dielectric material, and can greatly promote the popularization and application of materials of the system.