Abstract: Based on the photo-isomerization and hydrophobic property of azobenzene (AZO), as well as the hydrophilicity of polyethylene glycol (PEG), a novel kind of amphiphilic polymer (PEG-AZO-PEG) with photo-responsibility was synthesized. The photo-isomerization behaviors of PEG-AZO-PEG in diffe-rent conditions were studied through UV-Vis spectra. The photoresponsive micelles of PEG-AZO-PEG were prepared by solvent evaporation method. The load and release behaviors of micelles were studied using ibuprofen as model hydrophobic molecules. Results show that the isomerization rate can be regulated by tailoring the kind of solvent, pH value and the concentration of PEG-AZO-PEG. The accumulated release amount of ibuprofen increases remarkably under UV irradiation due to the disassembly of micelles. Besides, the accumulated release amount increases with the increase of pH value.