Abstract：Objective To study the effects of adriamycin on expression of KIF4A protein in MCF-7 cells. Methods During different period of time after the cells treated with adriamycin, the expression level of KIF4A protein was detected by western blotting. Then, 96 hours after the MCF-7 cells were treated with different concentration of adriamycin, the expression of KIF4A protein was monitored by western blotting, and at the same time the senescent MCF-7 cells were measured by using the method of senescence associated-β-galactosidase stain. Results Compared with the untreated MCF-7 cells, the expression level of KIF4A protein in the MCF-7 cells treated with adriamycin was significantly decreased. The MCF-7-cells positive for the senescence associated-β-galactosidase marker were increased from 5% to 42% by 1μmol•L-1 of adriamycin. Meantime, the positive staining MCF-7 cells exhibited a characteristic enlarged and flattened morphology. Conclusion The expression of KIF4A protein decreased in MCF-7 cells treated with adriamycin. The relationship between the reduced expression of KIF4A and the cellular senescence remains to be further elucidated.