Many nature materials have hierarchical structure, and its last cascade is always on a molecule scale, e. g., double-stranded DNA, making the hierarchy effective with minimal building blocks. Now artificial hierarchy can begin with a nanoscale level to embody the material with remarkable and fascinating properties which can be never achieved using non-hierarchical structure. A strong desire to fabricate some biomimicking hierarchies from a molecule level has been stimulating scientists. Herein we show that molecular structure can be easily controlled by a long and narrow tube, and self-assembly of macromolecules can be achieved to improve its crystallinity with plenty of excellent properties. We anticipate this paper to be a starting point for more sophisticated fabrication of fibers with self-assembly of macromolecules. nema