The invention discloses high-entropy rare earth zirconate ceramic capable of simultaneously stabilizing A-site and B-site cations and a preparation method of the high-entropy rare earth zirconate ceramic. The rare earth zirconate ceramic comprises a substance with a chemical formula of A2B2O7, wherein the A-site cation is a mixture of four or more metal cations of Sc, Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, and different metal cations in the A site have the same molar content; the B-site cation is a mixture of three or more metal cations of Ti, Hf, Sn, Th and Ce and Zr ions, and different metal cations in the B site have the same molar content. The rare earth zirconate ceramic prepared by the invention has the characteristics of low thermal conductivity, high hardness, excellent fracture toughness, high phase purity, high density and the like.