Nanoparticles conjugated with antibody were designed as active drug delivery system to reduce the toxicity and side effects of drugs for acute myeloid leukemia(AML).Moreover,methotrexate(MTX)was chosen as modeldrug and encapsulate within folic acid modified carboxymethylchitosan(FACMCS)nanoparticles through self-assembling.The chemicalstructure,morphology,release and targeting of nanoparticles were characterized by routine detection.It is demonstrated that the mean diameter is about 150 nm,the release rate increases with the decreasing of p H,the binding rate of CD33 antibody and FA-CMCS nanoparticles is about 5:2,and nanoparticles can effectively bind onto HL60 cells in vitro.The experimentalresults indicate that the FA-CMCS nanoparticles conjugated with antibody may be used as a potentialp Hsensitive drug delivery system with leukemic targeting properties. Nanoparticles conjugated with antibody were designed as active drug delivery system to reduce the toxicity and side effects of drugs for acute myeloid leukemia (AML). Moreover, methotrexate (MTX) was chosen as modeldrug and encapsulate within folic acid modified carboxymethylchitosan (FACMCS) nanoparticles through self-assembling. The chemicalstructure, morphology, release and targeting of nanoparticles were characterized by routine detection. It is said that the mean diameter is about 150 nm, the release rate increases with the decreasing of p H, the binding rate of CD33 antibody and FA-CMCS nanoparticles is about 5: 2, and nanoparticles are capable of binding onto HL60 cells in vitro. The experimental results indicate that the FA-CMCS nanoparticles conjugated with antibody may be used as a potential p Hsensitive drug delivery system with leukemic targeting properties.