A　dense　and　three-layered　ZrB2-ZrSi2-MoSi2　composite　coating　with　continuous　interlayer　interfaces　and　a　thickness　of　similar　to　270　mu　m　was　in-situ　prepared　on　Ta-10　W　alloy　by　plasma　spraying　and　pack　cementation.　Subjected　to　plasma　ablation　at　9.8　MW/m(2)　for　1000　seconds,　the　coating　with　a　mass　ablation　rate　of　0.0002　mg/s　undergoes　oxidation　to　form　a　skeleton-structured　ZrO2　and　liquid　self-sealing　SiO2.　During　the　ablation,　the　over-diffused　silicon　top　layer　of　the　coating　with　high　silicon　content　and　uniform　phase　distribution　can　produce　relatively　adequate　SiO2　to　withstand　the　consumption　for　up　to　1000　seconds,　yielding　excellent　ablation　resistance　above　2000　degrees　C.