The SiC/SiO2 nanochains heterostructure with double amorphous layers was successfully synthesized by a catalyst-free chemical vapor deposition process at 1280°C. The SiC/SiO2 nanochains experience an apparent regular periodic structure, whose SiO2 beads with diameters of about 160 nm are positioned on the SiC strings beside one another. Their growth mechanism could be mainly ascribed to Rayleigh instability and vapor-solid mechanism. The double layers structure of amorphous silica on the surface of the strings results from the different silica deposition stages. SiC nanowires with diameters of 20–50 nm were also found accompanied with the SiC/SiO2 nanochains and not changed into the chains-shaped morphology because of their small diameters and much higher additive surface pressure of bending silica melt layer on the nanowires.