In this paper, we report the growth of bamboo-like silicon-doped boron nitride nanotubes via catalyst-assisted pyrolysis of a boron-containing polymeric precursor. The morphologies and structures of the nanotubes were characterized using electron microscopy and Raman spectroscopy. Two types of nanotubes are observed, one from a base-growth mode and the other from a tip-growth mode. The type II nanotubes contain encapsulated catalytic nanoparticles at the tip of every compartment. This unique structure is a promising candidate for applications in many nanodevices.