The　experimental　results　show　that　needled　C/SiC　composite　exhibits　nonlinear　stiffness　characteristics　in　the　process　of　vibration.　In　order　to　consider　the　effect　of　the　number　of　fiber　layers　on　the　fatigue　properties,　the　S-N　curve　related　to　the　number　of　0　degrees　layer　fibers　for　needled　C/SiC　composite　is　proposed　in　this　investigation.　According　to　the　relationship　between　the　frequency　response　curve　and　the　signal　strength,　an　amplitude　probability　density　function　under　narrow　band　random　vibrations　was　proposed　for　predicting　the　fatigue　life　for　the　notched　plate　specimen.　The　results　showed　that　the　proposed　method　has　a　good　prediction　effect.