Water solution of PCL-PEG-PCL triblock copolymer has low critical solution temperature, which can be used to prepare thermosensitive hydrogel and can be used as drug carrier in biomedical field. β-cyclodextrin derivatives were used as molecule capsules, which improve water solubility of hydrophobic drug and improve drug loading and release ability of PCL-PEG-PCL hydrogel to hydrophobic drug. Quercetin was used as model hydrophobic drug in the experiments. The solubility of quercetin was greatly improved because microcapsule packaging structure was formed by complexation between quercetin and β-cyclodextrin; blended solution was also formed by quickly solving of PCL-PEG-PCL triblock copolymer in quercetin/ β-cyclodextrin derivatives water solution, which quickly changed to hydrogel state when temperature rise to human body temperature. Slow releasing experiments of quercetin were carried out in buffered solution, slow releasing effect of hydrophobic drug by PCL-PEG-PCL hydrogels realized, and β-cyclodextrin derivatives also acted as drug carrier in the slow releasing process.