Objective To obtain stable arsenicresistance cells, the fetal bone marrow mesenchymal stem cells (BMSCs)were exposed to lowlevel arsenite for 18 weeks. Methods Cells from 4 months fetal bone marrow were cultured in αMEM medium to obtain BMSCs. After 24h cytotoxicity test of the fetal BMSCs, we chosed 1?μmol/L NaAsO\-2 to be the dose under which the cell deathrate was 5%10%. The fetal BMSCs were exposed to lowlevel arsenite. MTT was used to detect the survival rate and IC50 of arsenicexposed cells and the control cells, which can reflect the change of arsenic tolerance. A hydride generationatomic fluorescence spectrometry method was used to detect arsenic in the arsenicresistance cells and the control cells. In order to study the mechanism of arsenicresistance, we also examined the intracellular GSH and GST content in the arsenicresistance cells and the control cells. Results The fetal BMSCs were continuously exposed to 1?μmol/L NaAsO\-2. Parallel cells were cultured in medium without arsenic provided passagematched control. After the fetal BMSCs were continuously exposed to low level NaAsO\-2 for 18 weeks, cells exhibited dramatic resistance to acute arsenite toxicity. Compared to control cells, arsenicresistance cells showed reduction in arsenic accumulation in cells. The