To improve the toughness and bonding strength with C/C composites of SiC coating, SiC nanowires have been fabricated on C/C composites by chemical vapor deposition method using methyltrichlorosilane as precursor at standard atmospheric pressure and the effect of synthesis temperature on the phases, morphologies and structures of nanowires were investigated. The phases, morphologies and structures of asreceived nanowires were characterized by XRD, SEM, TEM and EDS. The results show that pure SiC nanowires can be prepared at the temperature of 1300 ℃, the SiC nanowires are straight with smooth surface and the orientation is randomly distributed in a network. The SiC nanowires’ diameters are in the range of 100~160 nm, and lengths are up to hundreds of micrometers. The phases of nanowires change from βSiC and Si to single βSiC with the temperature increasing, and the Si phase is doped with SiC nanowires in the form of single crystal Si nanowires. Moreover, the deposition rate, output and density of the SiC nanowires are observably improved with the increase of synthesis temperature.