Abstract: Molecular dynamics(MD) method was employed to study the crystallization mechanism of polyethylene (PE) molecules on the surface of boron nitride nanotubes and boron nitride thin films. By analyzing the crystal conformation of PE molecule, the distribution of atoms and the molecular diffusion characteristics during crystallization, it was found that the ability of boron nitride nanotubes inducing crystallization of PE was much higher than that of boron nitride film layer, which demonstrating that the dimensions of the nanoscale materials affected the crystallization properties of polymer materials.