The purity and yield issues are significant challenges for the practical applications of nanoheterojunctions in functional devices. In the present work, we report the mass production of SiC/SiO_x nanochain heterojunctions via pyrolysis of polymeric precursors. The as-synthesized nanochain heterojunctions were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The composition of the raw materials played a critically important role in the formation of SiC/SiO_x nanochain heterojunctions. As compared to the reported works, our synthesized SiC/SiO_x nanochain heterojunctions exhibit much higher purities with a very uniform size distribution and fascinating microstructures, which make them promising to be utilized as optoelectronic nanodevices.