High fracture toughness of 8 YSZ (8wt% yttria-stabilized zirconia) is linked to its ferroelastic toughening mechanism. In this work, the similar ferroelastic domain is detected in monoclinic Dy1-xTa1-xZr2xO4 ceramics, which derives from the ferroelastic transformation between the high-temperature tetragonal (t) and low-temperature monoclinic (m) phase. The lowest thermal conductivity of Dy1-xTa1-xZr2xO4 ceramics is reduced by 30% compared with 8 YSZ, and the largest thermal expansion coefficients (TECs) is up to 11x10(-6)K(-1) at 1200 degrees C, which is comparable to that of 8 YSZ. Notably, the systematic investigations containing phase, microstructure, thermophysical properties of Dy1-xTa1-xZr2xO4 ceramics will provide guidance for its high-temperature application, especially as thermal barrier coatings.