Abstract: A male employee,aged 46,worked on the top of coke oven for 17 years with the record of three times abnormal result in routine blood test since 2005 admitted into Wuxi Hospital of Occupational Disease Sep.14 2010.Chief complain was granulocytopenia for 5 years as well as dermal petechia for two days.Routine blood examine revealed:white blood cell 4.5& #215;10⁹/L,red blood cell 3.2& #215;10⁹/L,hemoglobin 120 g/L,blood platelet 18& #215;10⁹/L.Marrow examination indicated MOS-RCUD-RT (myelodysplastic syndrome-refractory cytopenia with unilineage dysplasia-refractory thrombocytopenia,WHO Classification 2008).The case was complicated with type Ⅱ diabetes and acute bronchitis.The patient palliated after medication and discharged on Oct.16.Discussion was attached to emphasize the severity of myelodysplastic syndrome and draw attention for prevention and avoidance of its occurrence.