Abstract: A four arm star-shaped pH responsive polymer adamantane-poly(lactic-co-glycolic acid)-b-poly(N, N′-diethylaminoethyl methacrylate)-poly(ethylene glycol) monomethyl ether₄ was synthesized using adamantane as core. Self-assembly micelles of the synthesized polymer were prepared and the controlled release properties were further investigated. The results showed that the proportion of PDEAEMA had important effects on the properties of polymeric micelles, reflected by the fact that polymeric micelles with longer PDEAEMA segment had larger particle size, better drug loading capacity and higher cumulative drug release. Furthermore, the polymeric micelles had desired stability (CMC 0.0031 mg/mL), good pH-responsive function and high drug loading capacity (up to 24.8%). Under the simulated environment of tumor tissue (pH=5.0), the cumulative release of DOX-loaded micelles (85.2%) was significantly higher than those under the simulated environment of normal tissue (pH=7.4, 20.9%), indicative of the well-controlled release behavior of drug-loaded micelles. In conclusion, such pH-responsive polymeric micelles 4sAd-PLGA-D-P present great potential in the field of anticancer drug delivery.