OBJECTIVE： To prepare adriamycin-loaded PLGA-PLL-PEG nanoparticles， and study its antitumor activity. METHODS： PLGA-PLL-PEG with the polymerization of PLGA-PLL and activated polyethylene glycol was used as carrier for adriamycin， and adriamycin-loaded PLGA-PLL-PEG nanoparticles were prepared. The shape size， particle size distribution， adriamycin content of nanoparticles were detected， drug loading and encapsulation efficiency were calculated. Cumulative release rate （Q） of nanoparticles and adriamycin within 144 h and its proliferation inhibition rate on breast cancer HeLa cells were compared， and half inhibitory rate （IC50） was calculated. RESULTS： Prepared adriamycin-loaded PLGA-PLL-PEG nanoparticles were regular circular with good dispersion and no adhesion. The average particle size was （136.7±9.3） nm （n＝5）， average encapsulation efficiency was （76.67±8.63）％， average drug loading was （3.86±0.55）％ （n＝3）. Q12 h of adriamycin had reached 100％； Q12 h of adriamycin-loaded PLGA-PLL-PEG nanoparticles was 52.9％， Q144 h was 81.2％. The inhibitory rate of adriamycin-loaded PLGA-PLL-PEG nanoparticles on HeLa cells increased slowly than adriamycin； IC50 were 1.844， 0.345 μg/mL， respectively. CONCLUSIONS： Adriamycin-loaded PLGA-PLL-PEG nanoparticles are prepared successfully， showing good sustained-release effect and more significant inhibitory effect than adriamycin.