Abstract: Objective To explore the inhibitory effect of all-trans retinoic acid（ATRA）and arsenic trioxide（As2O3）on the growth of human endometrial cancer HEC-2B cells in vitro and its relation with N-myc downstream regulated gene1（NDRG1）protein. Methods Tetrazolium salt assay（MTT）was used to compare the inhibitory effect of different concentration of ATRA（1×10-7,5×10-7,1×10-6,5×10-6 and 1×10-5mol/L）and As2O3（1.0, 2.0, 4.0, 8.0 and 16.0μmol/L）on the growth of HEC-2B cells. The expression of NDRG1 protein was determined by Western blotting analysis. Results After treated with ATRA and As2O3 for 48h，the HEC-2B cells showed apoptotic change. ATRA 1×10-7-1×10-5mol／L and As2O3 1.0-16.0μmol／L inhibited the cell proliferation in a dose-and time-dependent manner. Western blotting method showed that ATRA and As2O3 down-regulated the expression of NDRG1 protein in a dose-dependent manner. Conclusion ATRA and As2O3 can significantly inhibit the growth of human endometrial cancer HEC-2B cells in vitro. The effect may be related to the down-regulation of NDRG1 protein expression.