MMCs wire can be produced by infiltration of molten metal into carbon fiber bundles. To protect the fibers from damage, the desized fibers must be pretreated before fabrication into wire. This paper deals with the formation of SiO2 coating on the carbon fibers using plasma chemical method and compares the coating produced by plasma method with the one by sol-gel method. The SiO2 coating produced by the sol-gel method on the carbon fibers is very rough. It is also discovered that the quality of the SiO2 coating is controlled by the power of plasma equipment and the flow rate of plasma gases. As the power of the plasma equipment and the flow rate of plasma gases increased, the coating surface became smoother.