A new method is used to grow macroscopic multi-walled carbon nanotube (MWNT) bundles with uniform diameter in bulk quantities. The diameter of the bundles are about 15–25 μm and their length is over 500 μm. The CNTs in each bundle are closely compact and parallel to each other along the direction of the bundle axis, which have potential applications as a composite enhancer or a high-strength nanostructure. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman analysis have been used to evaluate the morphological and structural features of such nanotube-based material. The formation mechanism of the bundles is discussed.