Abstract: Objective：To conclude the clinical experience of acquired factor Ⅴ deficiency (AFVD).Methods：Clinical data of 10 cases with acquired coagulation factor Ⅴ deficiency were analyzed retrospectively, the clinical features were analyzed and clinical experiences were concluded. Results：The 10 patients included 7 males and 3 females. Their ages varied from 51 to 71 with a median age of 60 years. No one had hereditary coagulation factor deficiency or family history. Patients with acquired coagulation factor Ⅴ deficiency had different manifestations, including spontaneously mucous bleeding, epistaxis, hematuresis, melena and encephalic bleeding. Laboratory test showed that all patients had prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT), decreased FⅤ activity, positive results of inhibitor qualitative or quantitative test. They were all diagnosed with acquired coagulation factor Ⅴ deficiency. All patients had fresh frozen plasma transfusions and were treated with steroid and immunosuppressive agents. There were 5 of the 10 patients had a remission and stopped bleeding, 3 of the 10 patients had poor therapeutic effect with steroid and cyclophosphamide, but had effective result with rituximab, 2 of the 3 patients had a normal level of FⅤ activity after treatment of rituximab and stopped bleeding, 1 of the 3 patients needed maintenance treatment of low dose rituximab, 2 of the 10 patients died of encephalic bleeding. Conclusions：Acquired factor Ⅴ inhibitor is a rare coagulation disorder with variable clinical symptoms. Steroid, cyclophosphamide and rituximab may be effective to eliminate the inhibitors.