SiC nanorods have been synthesized by means of the carbon nanotubes-confined reaction between SiO gas and carbon nanotubes. The diameters of SiC nanorods can be controlled by the local partial pressure of the CO gas produced during reaction. The morphology of SiC nanorods depends on the shape of the carbon nanotubes at high reaction temperatures. The growth mechanism of SIC nanorods is basically a shape memory synthesis.