TiC/SiC　and　TiN/SiC　composite　ceramics　were　fabricated　by　using　filter　paper,　phenolic　resin　and　titania　as　raw　materials　through　molding,　curing,　drying,　carbonization,　and　Si　infiltration　process.　The　phase　composition　and　microstructure　of　the　TiC/SiC　and　TiN/SiC　composite　ceramics　were　investigated　by　X-ray　diffraction　and　scanning　electron　microscopy,　and　the　bending　strength　and　fracture　toughness　of　the　composite　ceramics　were　measured.　The　results　show　that　the　TiC/SiC　composite　ceramic　formed　from　liquid　Si　infiltration　in　vacuum　has　porous　microstructure.　The　dense　TiN/SiC　composite　ceramic　formed　from　liquid　Si　infiltration　at　nitrogen　atmosphere　has　higher　bending　strength　and　fracture　toughness　than　which　of　porous　TiC/SiC　composite　ceramic.　The　different　microstructures　of　these　composite　ceramics　are　originated　from　the　different　wetting　angle　of　TiC　and　TiN　in　liquid　silicon.　The　tension　stress　and　compression　stress　are　formed　on　the　interface　between　the　additive　and　matrix　due　to　the　introduction　of　TiN　particles　in　TiN/SiC　composite　ceramic,　and　the　fracture　toughness　increases　as　the　direction　of　crack　changes　in　this　area.