Abstract: Objective To investigate the efficacy and risk factors of decitabine in the treatment of patients with myelodysplastic syndrome(MDS). Methods The clinical materials of 65 MDS patients with decitabine were collected. Relationships between efficacy and age, course of disease, grouping of International Prognostic Score System(IPSS), platelet count were analyzed. The risk factors affecting efficacy of decitabine in the treatment of MDS were analyzed. Results The total effective rate was 78.46% in all the patients. Age, course of disease, grouping of IPSS and platelet count were significantly correlated with the efficacy of decitabine in the treatment of MDS(P<0.05). Logistic regression analysis showed that older age, long course of disease, high grouping of IPSS and low platelet count were the risk factors affecting the efficacy of decitabine in the treatment of MDS(OR>1, P<0.05). Conclusion The decitabine is effective in the treatment of MDS, and its efficacy is related with age, course of disease, grouping of IPSS and platelet count.