OBJECTIVE:To prepare redox-responsive pluronic F127 micelles with high drug-loading efficiency. METHODS:The thiol derivative F127-SH with strong hydrophobicity was synthesized by introducing tert-butyl methacrylate and cysteamine to the hydrophobic segments of F127. Paclitaxel (PTX)-loaded redox-responsive pluronic F127 micelles with high drug-loading effi-ciency(F127-SS/PTX)were prepared by film-hydration method as well as oxidation reaction of thiol groups. The diameter,encap-sulation efficiency and drug-loading amount were detected,and the change of diameter and drug release behavior of micelles were investaged under reducing environment or non-reducing environment. RESULTS:Mean diameter of F127-SS/PTX micelles was about(77.87±1.79)nm,and encapsulation efficiency and drug-loading amount were(92.73±2.35)% and(16.25±0.99)%,re-spectively. The diameter of the micelles increased rapidly and drug release rate of PTX increased significantly in the presence of 10 mmol/L dithiothreitol. CONCLUSIONS:The redox-responsive pluronic F127 micelles with high drug-loading efficiency are pre-pared successfully.