A precursor polymer PI-OH was prepared by polycondensation of a diamine monomer with hydroxyl groups(HAB) and a dianhydride monomer(6FDA) in solution．Then cinnamoyl chloride was reacted with the hydroxyl-containing precursor to prepare the photosensitive polymer PI-CI．The photosensitivity of PI-CI was studied by using UV-Vis and FTIR．After being processed by linear polarized polymerization(LPP)

the spin-coated films of PJ-CI were used as photo-alignment layers to assemble sandwich-type liquid crystal cells via a capillary action using a nematic liquid crystal 5CB．The observation of polarizing microscopy showed that the PI-CI photo alignment layers had the ability to align LC molecules．The alignment was meliorated with a longer irradiation time．The photosensitive polymer PI-CI synthesized in this work is promising for the application as photo-alignment layers for liquid crystal displays．