The present disclosure provides a high-entropy rare earth-toughened tantalate ceramic. The ceramic is prepared by sintering Ta2O5 powder and x types of different RE2O3 powder, 4≤x≤9, and the molar ratio of the RE2O3 powders is 1. RE2O3 powder and Ta2O5 powder having the molar ratio of RE to Ta being 1:1 are weighed, a solvent is added for mixing, and ball milling is performed by a ball mill to obtain mixed powder M; the powder M is dried at a temperature of 650-850° C. for 1.5-2 h to obtain dried powder; the powder is sieved to obtain powder N, the powder N is placed in a mold for first pressing to obtain a rough blank, and the rough blank is then pressed for the second time to obtain a compact blank; the compact blank is sintered to obtain the high-entropy rare earth-toughened tantalate ceramic.