A strategy to prepare interconnected carbon nanofibers using an electrospinning technique is proposed. This strategy lies in the addition of poly(acrylonitrile-co-butadiene (PAN-co-PB) copolymer in a precursor solution composed of polyacrylonitrile (PAN) and N,N-dimethylformamide. During pyrolysis, PB decomposed, softening the fibers and creating the possibility of fiber-fiber connection. The fiber diameter decreased with an increase in the PAN-co-PB content. Further addition of PAN-co-PB caused the fusion of neighboring fibers, which enlarged the fiber diameter and decreased the specific surface area of fibers. The microcrystallite sizes of carbon nanofibers depended on the PAN-co-PB content; and the addition of PAN-co-PB promoted the development of ordered graphite crystallites. The interconnected carbon nanofibers exhibited an electrical conductivity four times larger than that of the nanofibers with a uniform separated fibrous structure. The purpose of this work is to prepare carbon nanofiber mats with good electrical conductivity and well-controlled morphology for further use as energy-associated devices and catalyst supports.