〔Abstract〕 Objective To analyze the clinical features, the efficacy of131I therapy and its effect on granulopoiesis in Graves′ hyperthyroidism(hyperthyroidism) patients with neutropenia. Methods 144 hyperthyroidism patients were retrospectively studied after131I therapy, among which 42 cases(HT group) accompanied neutropenia due to hyperthyroidism itself, 52 cases(ATD group) appeared neutropenia after anti-thyroid drug(ATD)treatment, and the remaining 50 cases(control group) were hyperthyroidism patients with normal neutrophil count. The clinical features, the efficacy of131I treatment for hyperthyroidism and the change of neutrophil count after131I treatment were analyzed and compared in three groups.Results Mild neutropenia was commoner in both the HT group and the ATD group. The curative rate of hyperthyroidism in the HT group, the ATD group and the control group were80. 95%, 84. 62% and 84. 00%, respectively. There was no significant difference in the efficacy of131I therapy among the three groups. Compared with the baseline value before treatment, neutrophil count increased in all three groups 2-4 weeks after131I treatment(allP<0. 05). The neutrophil recovery rates of the HT group and the ATD group were 61. 90% and 84. 62%, respectively. The ATD group had a higher recovery rate(P<0. 05).Conclusion Mild neutropenia is commoner in hyperthyroidism patients with neutropenia due to either hyperthyroidism itself or ATD treatment. Normative131I treatment for hyperthyroidism patients with neutropenia is safe and effective.