Poly(p-anol-formaldehyde) cinnamates(AGEFCs) were synthesized to prepare a photo-sensitive polymer which enabled to be photodimerized via 6-center reaction. The photocharacteristics of the mixture of the AGEFCs and a sensitizer after exposure to light was tested. The yield of the residual film, which was closely related to the sensitivity of the film, was affected by the degree of polymerization of the backbone resin, sensitizers and their concentration. AGEFC-3 revealed a good photosensitive effect such as about 73% yield of residual film at 128 min. of exposed time.