OBJECTIVE： To prepare the norcantharidin （NCTD） nano-micelle and study its antitumor effect. METHODS： NCTD nano-micelle was self-formed in water using Triblock copolymers distearyl phosphatidylethanolamine-polyethylene glycol-maleimide； its shape was observed， the drug-loading rate， entrapment efficiency， particle size， Zeta potential were investigated. MTT was used to investigate the cell survival rate of human lung cancer A549 cells in negative control group （Phosphate buffer solution）， carrier group （blank nano-micelle）， positive control group （NCTD APIs， 5-320 μg/mL） and NCTD nano-micelle group （NCTD， 5-320 μg/mL） after acting different time （24， 48， 72 h）. Tumor nude mice were randomly divided into blank control group， NCTD injection group （1 mg/kg）， NCTD low-dose， high-dose groups （0.5， 1 mg/kg）， 6 in each group. All mice were intravenously injected relevant medicines in tail， once a day， for 8 weeks. Tumor size was measured every week， and tumor quality was detected after the second day of finishing administration. RESULTS： NCTD nano-micelle was round， drug-loading rate was （2.82±0.05）％， entrapment efficiency was （83.67±1.78）％， particle size was （138.6±45.8） nm， Zeta potential was －（12.75±0.34） mV （n＝6）. Cell survival rate of A549 cells in carrier group had no obvious changes， and was obviously decreased in positive control group and NCTD nano-micelle group， which was positively correlated with concentration and time. And the decrease degree of cell survival rate in NCTD nano-micelle group was stronger than positive control group （P＜0.01）. Compared with blank control group， the tumor quality of mice in 3 administration groups was reduced （P＜0.05）， the reduction degree in NCTD nano-micelle high-dose group was stronger than NCTD nano-micelle injection group （P＜0.05）. CONCLUSIONS： NCTD nano-micelle is successfully prepared， which has good in vitro and in vitro anti-tumor effect on A549 cells.