A water-soluble photo-reactive chitosan derivative was synthesized as a novel anti-adhesive agent by combining low molecular O-carboxymethyl chitosan and photo-reactive N-(4-azidobenzoyloxy) succinimide. Photoreactive low molecular O-carboxymethyl chitosan was analyzed by Fourier transform infrared spectroscopy (FTIR) and proton nuclear resonance spectroscopy ($^1H$ NMR). Photo-immobilization of the polymer was confirmed using photo-mask and the degree of cross-linking was measured from the immobilized dried weight. The cytotoxicity of the photo-reactive low molecular O-carboxymethyl chitosan was confirmed by a MTT assay. In vivo animal study was performed to identify the synthetic material for antiadhesive effect. Furthermore, the protein release test that was performed to apply it as a drug-eluting anti-adhesive agent after bovine serum albumin (BSA), was immobilized to the photoreactive polymer. Because photo-reactive low molecular O-carboxymethyl chitosan has high water solubility as well as non-cytotoxicity and photoimmobilization, it may a suitable material for making drug-eluting antiadhesive agents.