Highly oriented rich boron B-C-N nanotubes, prepared by bias-assisted hot filament chemical vapor deposition, have been examined by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The compositions of the nanotubes have been analyzed by Anger electron spectroscopy and electron energy loss spectroscopy. The results show that the compositions can be controlled by changing the B2H6 concentration in the reactive gas mixture and the highest boron content of 45% at atomic percentage can be obtained for the B-C-N nanotubes. As a new kind of semiconducting material, the photoluminescence of the B-C-N nanotubes is also studied.