Abstract: Objective To observe the effect of amifostine on proliferation of K562 cells. Methods Amifostine was proportionally diluted to 0.2mg/ml,0.5mg/ml,0.75mg/ml,1.0mg/ml,1.6mg/ml,and 3.2mg/ml groups.K562 cells were incubated with different concentrations of amifostine and cell growth status was chronologically observed under a microscope.Cell proliferation was detected by CCK-8 assay and cell growth curve was plotted for calculating inhibition ratio. Results Amifostine could remarkably inhibit the proliferation of K562 cells with a cell doubling time of 48h.Amifostine inhibited the proliferation of K562 cells in a time-and dose-dependent manner.The proliferation of K562 cells was significantly inhibited 48h after treatment with amifostine at the concentration of 0.75mg/ml or higher（P＜0.05）.The greatest inhibitory rate was 91% in 3.2mg/ml amifostine group with numerous cells died. Conclusion Amifostine can inhibit the proliferation of K562 cells,which provides an experimental basis for the treatment of hematological toxicity which is correlated with chemotherapy for chronic myeloid leukemia with amifostine.