Myelodysplastic syndrome (MDS) is a group of heterogeneous diseases derived from hematopoietic stem cells characterized by hemolytic anemia and high risk of conversion to acute leukemia. MDS is an age-related disease in which approximately 80% of patients are over 60years of age, male and female. Anemia is the most common clinical condition, and many patients are also associated with infection and bleeding. When the amount of α globin synthesis is insufficient, the remaining β chain forms tetramer β4, i.e. HbH. The latter forms a precipitate in red blood cells, leading to hemolytic anemia, called HbH disease, the majority of which is congenital, a small number of patients with myelodysplastic syndrome and acute myeloid leukemia may appear HbH (called acquired HbH disease). We reported a 71years old male patient diagnosed as myelodysplastic syndromes (MDS) in our hospital. The patient has a negative α-thalassemia gene test. The H band is detected by hemoglobin electrophoresis. This article analyzed and discussed this case with MDS, as well reviewed MDS.