<p>Arbon/carbon (C/C) composites have emerged as ideal candidates for thermal protection systems in aerospace vehicles due to their exceptional high-temperature mechanical properties. However, their rapid ablation in high-temperature oxidative environments severely limits engineering applications. To address this bottleneck, this study proposes a ZrC-30vol.%SiC (ZS3) ultra-high temperature ceramic coating system with an SiC transition layer. The composite coating was fabricated on C/C substrates via vacuum plasma spraying technology, and its anti-ablation mechanisms were systematically investigated through multi-scale analytical approaches. A three-dimensional transient thermo-structural coupling model was established using the ANSYS software, incorporating the " birth and death element " technique to simulate dynamic evolution of coating ablation morphology. This enabled quantitative characterization of spatiotemporal temperature distribution and Gaussian-type temperature gradient characteristics under laser irradiation. Transient thermo-structural coupling analysis elucidated the thermal stress evolution mechanisms in the coating-transition layer-substrate system during ablation. Combined CO₂ laser ablation experiments and microstructural characterization revealed that the ZS3 composite coating exhibits significantly superior ablation resistance compared to pure ZrC coatings, attributed to the formation of a dense ZrO₂-SiO₂ oxide layer. The synergistic failure mechanism involving oxidative phase transformation and thermal stress was comprehensively revealed. This research provides theoretical foundations for damage assessment and optimized design of ultra-high temperature ceramic coatings under high-energy laser irradiation.</p>