Silicon carbide (SiC)/carbon nanocomposites exhibit outstanding physical properties as well as chemical stability and can be utilized in a variety of potential applications. To synthesize SiC/C nanocomposites requires high specific surface area, moderate agglomeration, and good interfacial interaction with the substrate. However, the synthesis of these desired SiC/C nanocomposites requires amelioration in two critical aspectsimproving the bond strength between C and SiC and dispersing SiC homogenously to avoid agglomeration. In this work, a Joule heating method is used to synthesize SiC/C necklace-like nanocomposite fibers from electrospun C/Si nanofibers. A controlled current is induced to heat the C/Si nanofibers to approximate to 2000 K, promoting the in situ reaction between Si nanoparticles and carbon fibers to create SiC nanoparticles. SiC nanoparticles are uniformly formed in the composites with high specific surface area and strong bonding with the carbon nanofibers. The synthesis of SiC demonstrates feasibility toward in situ fabrication of unagglomerated carbide nanoparticles on a carbon-based nanofiber with desirable interconnection bond strength.