Abstract: Polymeric nanotubes have great advantages in biological carrier applications due to their flexible structure design and large aspect ratio. The independence of self-assembly structure from molecular weight and molecular weight distribution is a major advantage of alternating polymers for self-assembly. In the present study, a series of amphipathic alternating copolymers with hydrophobic sections of different lengths by thiol-halogen click chemistry reactions are synthesized. The molecular weight and structure of three alternating copolymers are characterized by gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). These alternating copolymers self-assemble in water and dimethyl sulfoxide (DMSO) (volume ratio 4∶1) and form a series of ultrathin nanotubes with a wall thickness of only 1—2 nm. Through transmission electron microscope (TEM), it could be observed that as the length of the carbon chains in the hydrophobic sections of the alternating copolymers increases, the diameters of the nanotubes increase from 19.61 nm to 26.24 nm. Besides, through the software simulation of Chem3D, the hypothesis is verified that the alternating copolymer folds to form a sandwich structure and further self-assembles into nanotubes. The nanosheets assembled by alternating copolymers with longer hydrophobic sections are thicker, the bigger bending stress resulting in the formation of larger diameter nanotubes which are more thermodynamically stable. Biological carriers need on-demand release when they reach the target. Therefore, the carriers generally required to have the ability to controllable release or disintegrate. In this study, the hydrophobic thioether bonds in alternating copolymers are transformed to the sulfone bonds after oxidation. The better water solubility of sulfone bonds will enhance the hydrophilicity of the alternating copolymers, which caused the tubular structure of the nanotube to decompose after oxidation by H₂O₂ at 37 °C for 2 h. The large aspect ratio and controlled degradation of these nanotubes may have potential applications in biological delivery and controlled releasing.