Abstract： Objective To investigate the correlation between the chromosomal abnormalities and prognosis of the myelodysplastic syndrome (MDS) patients, and analyze the effects of treatment. Methods Karyotype analysis of 122 patients according to the international human cytogenetics (ISCN) criteria.Treatment of RA and RAS were mainly dependent on agents to induce differentiation of hematopoietic cells and drugs based.RAEB,RAEB-t,CMML treatment were dependent on low-dose chemotherapy and low-dose combination chemotherapy regimens. The treatments of 64 MDS patients with abnormal karyotype were analyzed and compared with control group, and 58 normal karyotype MDS patients were hospitalized in the same period.Results After treatments,17 cases gained complete remission among 64 patients with abnormal karyotype MDS patients.The CR rate was 26.6 ％.While in control group,30 gained CR in 58 MDS patients with normal karyotype. The CR rate was 51.7 ％. Comparing with the CR patients of normal karyotype, the number of patients with abnormal karyotype of CR was significantly lower (x 2 =8.1 3,P ＜ 0.05).Conclusion Karyotype analysis shows important significance in the diagnosis and prognosis of MDS. Karyotype transformation demonstrates differently in the risk of leukemia progress.