Conical carbon fibers (CCFs) with carbon nanotubes (CNTs) as their cores were grown on graphite substrates with an improved chemical vapor deposition (CVD) method. The CNT core filaments demonstrated good mechanical strength probed by a scanning electron microscope. Furthermore, field emission currents around 100 muA were also attained from individual CNTs. The method has provided a convenient and inexpensive approach to mass assembling CNTs to a carbon substrate