Through the carboxymethylation reaction of dextran to synthesize carboxymethyl dextran (CMD). With glycyrrhetinic acid (GA) as the hydrophobic group and cysteamine (CYS) as the linking arm, the glycyrrhetinic acid-cysteamine (GA-SS-NH2) was synthesized through amidation reaction. Then through the amidation reaction of CMD and GA-SS-NH2, a kind of amphiphilic polymer carboxymethyl dextran-cysteamine-glycyrrhetinic acid (CMD-SS-GA) was synthesized. Ultimately, the redox-responsive drug-loaded micelles encapsulating doxorubicin (DOX) were prepared via self-assembly, which is CMD-SS-GA/DOX. The structural composition and morphology of CMD, GA-SS-NH2, CMD-SS-GA, and CMD-SS-GA/DOX were characterized by using MS, FTIR, 1HNMR, DLS, and TEM. The carboxymethyl substitution degree of CMD was determined by the back titration method, and the hydrophobic group substitution degree of CMD-SS-GA was determined by the 1HNMR method. Through the drug release experiment, the redox sensitive drug release feature of CMD-SS-GA / DOX was tested. The results showed that the carboxymethyl substitution degree of CMD was 2.04 and the hydrophobic group substitution degree of CMD-SS-GA was 0.32 to 0.83. The CMD-SS-GA / DOX prepared under the optimal conditions was a uniform spherical shape, with an average particle size of 117.7 nm and a polydispersity coefficient (PDI) of 0.139. The loading capacity and encapsulation efficiency were 11.6% and 57.1% respectively. The cumulative release amount of DOX of CMD-SS-GA / DOX in 10 mmol/L glutathione phosphate buffer solution (pH = 6.5, 7.4) within 24 hours reaches more than 80%, which has redox sensitivity.