In this study, the self-crimping process of multichain polystyrene into a carbon nanotube was investigated by molecular dynamics simulation. The simulation shows that multichain polystyrene arranged in parallel can self-crimp into a carbon nanotube and form a helix configuration. The formation mechanism illustrates that both the van der Waals potential well and the π–π stacking interaction between polystyrene and the carbon nanotube play a major role in the self-assembly process. Furthermore, some factors such as the chain number of polystyrene, the length of the polymer, the diameter of the carbon nanotube and the simulation temperature are also investigated. Moreover, different replaced polymers are shown, too. This theoretical research can provide valuable support for the design and manufacturing of hybrid structures in the fields of advanced composite materials and functional devices.