Thermal barrier coatings are mainly used as high-temperature protective materials on the surface of aero-engine turbine blades to reduce the service temperature of substrate effectively, and are a key technical means to further improve the service temperature and extend the service life of turbine blades. The stabilized yttrium oxide zirconia (YSZ) undergoes sintering and phase transformation in high-temperature environments, reducing the service life of thermal barrier coatings. Therefore, it is necessary to develop new thermal barrier coating materials. The NiCrAlY/YSZ/Sm2Zr2O7 and NiCrAlY/YSZ/ 0.8Sm2Zr2O7-0.2Y3Al5O12 thermal barrier coating system was prepared by the atmospheric plasma spraying technology in this work, and the phase structure and thermal conductivity of the thermal barrier coating system were systematically studied with XRD, DSC, SEM, etc. As a comparison, NiCrAlY/YSZ/Sm2Zr2O7 thermal barrier coating system was deposited by the atmospheric plasma spraying technology, and the properties of NiCrAlY/YSZ/Sm2Zr2O7 thermal barrier coating system were also tested under the same conditions. Then, its service behavior in a water-quenched thermal shock environment between room temperature and 1 150 ℃ was studied, and the phase evolution, failure mode, and failure mechanism of thermal barrier coatings were elucidated. The 0.8Sm2Zr2O7-0.2Y3Al5O12 coating deposited by atmospheric plasma technology contained amorphous phases. After 5 hours of heat treatment at 1 200 ℃, the SmAlO3 phase was discovered. Microcracks and pores were found on the surface and cross-sectional area of the 0.8Sm2Zr2O7-0.2Y3Al5O12 coating, which was the typical feature of preparing thermal barrier coatings by atmospheric plasmon spraying technology. Cracks were not found at the adjacent layers in the NiCrAlY/ YSZ/Sm2Zr2O7 thermal barrier coating system, indicating that the NiCrAlY/YSZ/Sm2Zr2O7 thermal barrier coating system possessed excellent adhesion. The thermal conductivity of the as-sprayed 0.8Sm2Zr2O7-0.2Y3Al5O12 coating approximately remained at 1.5 W/(m.K), but it slightly increased with temperature increasing from room temperature to 800 ℃. After annealing treatment at 1 200 ℃ for 5 h, its thermal conductivity was higher than that of the as-sprayed 0.8Sm2Zr2O7- 0.2Y3Al5O12 coating, which firstly decreased and then increased with the increase of temperature. The NiCrAlY/YSZ/Sm2Zr2O7 thermal barrier coating system failed after 12 cycles. The peeling layer was found inside the Sm2Zr2O7 layer in the NiCrAlY/ YSZ/Sm2Zr2O7 thermal barrier coating system since the Sm2Zr2O7 possessed lower fracture toughness. The NiCrAlY/YSZ/ 0.8Sm2Zr2O7-0.2Y3Al5O12 thermal barrier coating system failed after 90 cycles. While the peeling layer was found inside the YSZ layer in the NiCrAlY/YSZ/0.8Sm2Zr2O7-0.2Y3Al5O12 thermal barrier coating system, which indicated that the 0.8Sm2Zr2O7- 0.2Y3Al5O12 thermal barrier layer possessed excellent fracture toughness. Compared with the conventional NiCrAlY/YSZ/ Sm2Zr2O7 thermal barrier coating system, the cyclic service life of the NiCrAlY/YSZ/0.8Sm2Zr2O7-0.2Y3Al5O12 thermal barrier coating system increases by 7 times. The 0.8Sm2Zr2O7-0.2Y3Al5O12 is a potential candidate for the thermal barrier coating material.