In this manuscript, a multiple-helical core-shell structure is studied from polyphenyl and boron nitride nanotube (BNNT) through the molecular dynamics simulation. The results exhibited that polyphenyl is constrained in the inside of BNNT and self-coiled to a helical configuration. In these systems, both the van der Waals potential well and the -stacking interaction between the polyphenyl and BNNT play a key role in the formation of helical nanostructures. The final configuration of composites can be influenced by many factors such as the diameter of BNNT, the chain number of polymer, the length of polymer, and the simulation temperature which are investigated in detail. This theory research about polyphenyl and BNNT may supply more theoretical foundation in chemical functionalization and helical polymer synthesis, which can be helpful for fabricating nanoscale devices.