Highly N-aralkylated poly(p-phenylene terephthalamide) (PPTA) with various substituents having benzyl units in their structures were synthesized in a high yield, and their properties as a liquid crystal alignment film were studied. Good liquid crystal alignment and pretilt angles of 0.5 to 8.1 deg were observed on the spin-coated polymer films after rubbing when a nematic liquid crystal, ZLI-2293 was used. The induced pretilt angle showed no correlation with the surface-free energy of the polymer film, but was strongly dependent on the structure of the side chain. The effects of the structural difference of the side chain and type of liquid crystals are discussed in more detail.