Abstract: Curcumin, a polyphenolic natural extract of curcuma longa, exhibits a wide range of pharmacological influence including anti oxidant, anti inflammatory, and anti tumor activities in various preclinical models. However, the low systemic bioavailability of curcumin is also highlighted, which has been mainly attributed to its extremely low aquous solubility and severe liver first pass effect. In the present study, N t butoxycarbonyl phenylalanine (Boc Phe) terminated monomethoxyl poly(ethylene glycol) b poly(ε caprolactone) block copolymer (mPEG PCL Phe(Boc)) was synthesized and characterized by 1H NMR and gel permeation chromatography. The curcumin loaded mPEG PCL Phe(Boc) micelles were prepared by a solid dispersion method and showed significant improved stability in plasma compared with free curcumin upon parenteral administration. So the internal metabolism velcocity of curcumin was slow down and the bioavailabity was improved. The combination of parenteral curcumin micelle with doxorubicin resulted in enhanced tumor growth inhibition versus either single agent. Furthermore, a simultaneous decrease in doxorubicin induced systemic toxicity by curcumin loaded micelle was also observed. Overall, curcumin loaded micelle is a promising new formulation that is able to enhance the efficacy of chemotherapeutic drugs and combat multi drug resistance.