A dendritic amphiphilic block copolymer H40-poly(D,L -lactide)-block-D-alpha-tocopheryl polyethylene glycol 1000 succinate (H40-PLA-b-TPGS) is synthesized, which is then employed to develop a system of nanoparticles (NPs) loaded with docetaxel (DTX) as a model drug for cancer treatment due to its higher drug-loading content and drug encapsulation efficiency, smaller particle size, faster drug release, and higher cellular uptake in comparison to the linear PLA polymer NPs and PLA-b-TPGS copolymer NPs. The drug-loaded NPs are prepared by a modified nanoprecipitation method and characterized in terms of size and size distribution, surface morphology, drug release profile, and physical state of DTX. Cellular uptake of coumarin 6-loaded NPs by MCF-7 cancer cells is determined by flow cytometry and confocal laser scanning microscopy. The antitumor efficacy of the drug-loaded NPs is investigated in vitro by MTT assay and in vivo by xenograft tumor model. The 72 h IC50 of the drug formulated in the PLA, PLA-b-TPGS, and H40-PLA-b TPGS NPs is found to be, 1.5 +/- 0.3, 0.9 +/- 0.1, and 0.15 +/- 0.06 mu g mL(-1), which are 7.3, 12.2, and 73.3-fold effective than 11.0 +/- 1.2 mu g mL(-1) for Taxotere, respectively. Such advantages are further confirmed by the measurement of the tumor size and weight.