Abstract: One dimension,two dimension,three dimension Si-based nanowires were prepared separately by heating a mixture of SiC+ Fe powders,SiC+ Fe+ Co powders or SiC+ Co powders under an Ar atmosphere. Scanning electron microscopy （SEM）,high resolution transmission electron microscopy （HRTEM） and X-ray（EDX） analyses reveal that one dimension and two dimension Si-based nano-wires consist of C,Si,O. There are two genus nanowires,one is Si nanowires with SiOx wrapping layers, the other is SiC nanowires with SiOx wrapping layers.Three dimension Si-based nanowires has flower like structure and only consist of SiOx. The above SiOx and Si are of amorphous structure,SiC is β-SiC single crystal.