Ultra-high　temperature　ceramic　(UHTC)　is　one　of　the　most　promising　materials　used　in　thermal　protection　system　for　hypersonic　flight　vehicles.　In　this　work,　ZrB2–0.5　vol%　SiC　composites　are　fabricated　with　nano-sized　ZrB2　and　SiC　particles　by　spark　plasma　sintering　(SPS)　at　1500　°C.　The　average　density　of　the　composites　reaches　5.47　g　cm−3,　while　the　average　grain　size　is　only　1　μm.　Then,　single　and　cyclic　ablation　tests　are　conducted　using　a　plasma　generator.　Ablation　mechanisms　and　microstructure　evaluation　of　the　composites　are　discussed　in　detail.　In　addition,　a　digital　optical　microscope　system　is　adopted　to　obtain　the　surface　micrograph　after　ablation.　Results　show　that　ablation　center　will　become　protuberant　rather　than　form　an　ablation　crater,　due　to　the　relative　porous　and　loose　oxide　layer　and　flushing　action　of　ablation　flame.　Thickness　of　oxide　layer　and　mass　gain　of　the　sample　obviously　increase　during　the　single　ablation,　while　the　mass　change　rate　decreases　gradually　and　is　then　kept　stable　with　the　ablation　time　increasing.　Compared　with　the　single　ablation,　the　cyclic　ablation　leads　to　higher　mass　gain　and　mass　change　rate,　as　many　microcracks　formed　on　the　surface　which　will　significantly　accelerate　the　oxidation.　©　2018　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim