The　sol　dipping　and　in-situ　decomposition　method　was　used　to　prepare　3-D　carbon　fiber　braid/coating/Al2O3　ceramic　composite,　SiO2,　SiC　coating/3-D　carbon　fiber　braid　as　origin.　The　Influence　of　coating　on　oxidation　resistance　of　CF　braid,　the　mechanical　properties　and　fracture　mechanism　of　composite　were　characterized　by　isothermal　oxidation　weigh-loss,　XRD,　SEM,　electronic　tensile,　etc.　The　results　showed　that　the　oxidation　resistance　of　CF　braid　could　be　noticeably　improved,　and　the　interfacial　bonding　properties　of　fiber　with　ceramic　were　markedly　improved　by　gradient　coating,　the　mechanical　properties　of　composites　were　also　greatly　improved　(5-10　times),　and　the　fracture　model　was　changed,　compared　with　composite　without　coating.　Pulling-out　and　bridging　of　fiber　and　crack　deflection　induced　by　fiber　were　the　fracture　mechanism　of　composites.