An alignment method includes: (1) providing a substrate, applying a coating material formed from any two materials of aromatic dianhydrides, aromatic diamines or diamines containing biphenyl and hexyl in side groups; (2) sputtering a third material which is not coated in step (1) along a direction having an angle not equal to zero with the substrate for conducting a polymerization reaction with the two materials coated in step (1) to generate a reaction product; (3) thermally treating the reaction product. The diamine containing biphenyl and hexyl in side group reacts with the main group to form a side chain, and thus controls the pretilt angle while assisted with physical sputtering to sputter in a certain angle, thereby forming a pretilt direction.