Objective To study the effects of Multi-Walled Carbon Nanotube with different doses on the cellular proliferation of human embryo kidney 293 cells.Methods The cultured human embryo kidney cell line 293 was seeded into 96-well plates and various concentrations of Multi-Walled Carbon Nanotube were added into different groups of culture.Methyl thiazolyl tetrazolium(MTT)assay were applied to detect the cellular viabilities after being incubated with Multi-Walled Carbon Nanotube for 48 hours and the results were calculated with specific static software to protract the cell viability curve.Results The Multi-Walled Carbon Nanotube had different effects of inhibiting the multiplies of 293 cells depending on its concentrations.In addition,when the concentration of Multi-Walled Carbon Nanotube reached over 0.5ug/ml,the inhibition became significantly.Conclusions Multi-Walled Carbon Nanotube can penetrate the cell membrane of 293 cells to influence the activities of cells and the ability of proliferation will be decreased significantly when the concentration came to some degree.Therefore,the safety dosage of the Multi-Walled Carbon Nanotube on human normal embryo kidney 293 cells were estimated in this research.