Abstract: OBJECTIVE To prepare docetaxel(DTX) nanoparticles and study its anti-tumor activities in vitro and in vivo.METHODS The DTX-G2 nanoparticles were prepared via the method of anti-solvent precipitation combined high-pressure homogenization. Dynamic light scattering method was used to measure the particle size and scanning electron microscopy was used to observe the morphology. Drug release in vitro, the membrane toxicity and the cytotoxicity were studied. Anti-tumor effect in vivo was investigated on 4T1-bearing mice using Paclitaxel injections as the control at the dose of 10 mg·kg^-1. RESULTS The particle size of DTX-G2 nanoparticles was (356.8±6.709)nm with polydisperse index of 0.147±0.02 and a Zeta potential of (-14.4±0.07)mV, the drug loading capacity was (62.3±1.9)%. The nanoparticles exhibited schistose morphology in SEM. The accumulative release achieved 80.4% in 192 h. DTX nanoparticles presented no hemolytic activity, could be utilized via iv administration. MTT assay displayed that DTX-G2 nanoparticles had stronger cytotoxicity against 4T1 cells than solution (IC₅₀, 2.374 μg·mL^-1 vs 5.664 μg·mL^-1, P<0.05), the uptake ratio of nanoparticles was enhanced significantly(20.46 vs 11.01, P<0.05). The anti-tumor efficacy of DTX was promoted in vivo comparing with Paclitaxel injections (75.7% vs 52.4%, P<0.05). CONCLUSION The DTX-G2 nanoparticles present high drug-loading content, good stability, higher cellular uptake ability, and enhance anti-tumor efficacy which is expected to be a new drug delivery system in clinical trials of DTX.