OBJECTIVE To prepare and evalu ate doxorubicin-loaded red blood cell membrane chitosan-targeted nanoparticles of targeting tumor cell folate acid （FA）receptor（FA-RBC-DOX-CS-NPs）. METHODS Doxorubicin-loaded chitosan nanoparticles （DOX-CS-NPs） were prepared by ion cross-linking method. FA and amino polyethylene glycol phospholithin （NH2- PEG2000-DSPE）were covalently linked to modify the red blood cell membrane to construct FA-RBC-DOX-CS-NPS. FA-RBC- DOX-CS-NPs were characterized and investigated on in vitro drug release characteristics ，antitumor activity and endocytosis ability （investigation with human breast cancer MCF- 7 cells）. RESULTS Average particle size of FA-RBC-DOX-CS-NPs was （254.200± 2.651）nm，and polydispersity index was 0.199±0.031；Zeta potential was （－10.100±0.213）mV. FA-RBC-DOX-CS-NPs released fast in the tumor microenvironment （pH6.5）. Cellular experiments showed that ，the nanoparticles could inhibit the activity of MCF- 7 cell proliferation and improve the efficiency of endocytosis. CONCLUSIONS FA-RBC-DOX-CS-NPs are prepared successfully. The nanoparticles have good tumor cell targeting and endocytosis ability ，and can realize the enrichment of drugs in tumor cells.