Abstract: Coating silicon oarbtde (SiC) on the surface of carbon fibers (CFs) is a good way to improve the oxidation-resistance of Chs and resist interaction between GFs and metals at high temperature.In this paper chemical vapor deposition(CVD) have been used for coating SiC continuously. The investigation of dependency of canting thickness,deposition and crystal structure on deposition parameters have been conducted to obtain the mean activation energy of 165 KJ/mol in the system and main structure of β-SiC. And we emphatically analysed the strength of coating CFs and identified that the degrease in strength of SiC-coated GFs was caused by the chemical attack of H⁺ and other ions during GYD,existence of free silicon as well as residual stress.