Abstract: Paclitaxel(PTX), an effective anti-tumor drugs, is water-insoluble. And Cremophor as a solubilizer in its commercial formulation, Taxol^® , often causes side-effects which limit its antitumor effect. We designed and synthesized PEGylated carboxymethyl chitosan-rhein(CRmP)conjugate, and further prepared PTX-loaded CRmP polymeric micelles(PTX/CRmP). CRmP conjugate was characterized by fourier transform infrared spectrum(FT-IR)and nuclear magnetic resonance spectroscopy(¹H NMR). The particle size and surface morphology of PTX/CRmP were characterized by dynamic laser particle size analyzer(DLS)and atomic force microscope(AFM), respectively. The cytotoxicity of CRmP conjugate and PTX/CRmP against MCF-7 cells were evaluated by MTT assay. The results showed that CRmP conjugates displayed very low cytotoxicity and that PTX/CRmP exhibited better in vitro anti-tumor activity than Taxol^® at the same drug concentration after a long-term administration.