Thermal protection coatings for aerospace applications require robust mechanical properties, exceptional thermal insulation, and high impact resistance to safeguard critical hot-section components and thereby extend their service life. Previous studies have confirmed that high-entropy titanate (La_0.3K_0.1Ca_0.2Sr_0.2Ba_0.2)TiO_3+δ (HE-LKTO) materials have excellent thermal protection properties and mechanical properties. To evaluate the viability of the HE-LKTO for Thermal protection coatings, a novel high-entropy titanate coating with a non-equimolar A-site composition was fabricated via atmospheric plasma spraying. The as-sprayed coatings subsequently underwent a comprehensive analysis of their microstructure and phase structure. Guided by the experimental results, the coating prepared under the optimized conditions was systematically investigated for its thermal protection performance via plasma flame thermal shock testing. The failure mechanism was revealed by analyzing the coating’s dynamic behavior under extreme heat flux. Results show that the HE-LKTO coating prepared at 36 kW exhibits the optimal microstructure: the sprayed particles achieve complete melting and effective spreading, resulting in the lowest surface roughness and porosity. In addition, HE-LKTO coating maintains structural integrity at ablation temperatures of 1400 ℃, exhibiting excellent high-temperature protection performance. At the extreme temperature of 1600 ℃, however, the coating began to spall as a result of accumulated thermal stress induced by the mismatched thermal expansion coefficients between the coating and substrate, as well as crack propagation along interlamellar boundaries and interface separation. This work not only validates the great potential of HE-LKTO as thermal protection coatings but also provides crucial insights into its failure mechanism, laying a foundation for future performance enhancement.