We observed a new kind of supramolecule formed by molecular nanotubes and starpolymers on a highly oriented pyrolytic graphite (HOPG) by scanning tunneling microscopy. The molecular nanotube is an organic tubular molecule with the length of ca. 25 nm, synthesized from alpha -cyclodextrins. It was found that the molecular nanotube included a Linear polymer chain, poly(ethylene glycol) monocetyl ether, covalently fixed to a HOPG substrate. Furthermore, we determined that the molecular nanotubes and starpolymers formed a dendritic structure with three branches on a substrate.