Photocrosslinkable polymers are clean and convenient materials for the biomedical uses. Chitosan which owns excellent biocompatible and antimicrobial properties, is one of the choices while it is introduced with photosensitive functional groups. In this Study, chitosan was N-phthaloylated to react with acryloyl chloride in the organic solvent homogeneously and the result has been verified by the Solubility test. Fourier transformed infrared spectrometry and nuclear magnetic resonance spectrometer analysis indicated that the modification with the attachment of the photosensitive functional group, the acryloyl group, onto chitosan and poly(ethylene glycol) (PEG) was feasible. The differential scanning calorimetry analysis further indicated that the melting points of the N-phathaloylated chitosan were decreased as compared with the untreated chitosan control. Then photocrosslinkable chitosan derivative (CH-PAA) was photocopolymerized with PEG diacrylate (PEGA) under UV irradiation. The adhesion strength characterization and swelling capacity evaluation for this photocopolymer have shown obvious raises of the adhesiveness and water-adsorption abilities as compared with the photopolymer of CH-PAA. (c) 2006 Wiley Periodicals, Inc.