This paper presents a simple vapour deposition method for one-step synthesis of SiC//SiO2 core-shell heterostructured nanowires. The phases, structures and morphologies of the synthesized core-shell heterostructures are systemically studied by field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy. The results show that these heterostructures consist of a single crystalline SiC core of 20∼30 nm diameter covered by a uniform layer, about 15 nm thickness of amorphous SiO2. Such heterostructures were grown based on the vapour–solid mechanism and the deposition way has an important influence on their morphology. A unique optical property has also been found in their photoluminescence spectra that have blue shift relative to the bulk SiC.