Hemophilia is a group of bleeding disorders with inherited coagulation disorders, characterized by impaired active thromboplastin production, prolonged clotting time, a lifelong tendency to bleed after minor trauma, and “spontaneous” bleeding in severe cases without obvious trauma. So, how is hemophilia examined? The following are the screening tests for hemophilia: 1. Screening test: normal platelet count, bleeding time and clot retreat time, prolonged clotting time, partial thromboplastin time and prothrombin generation time, and shortened serum prothrombin time. 2, qualitative experiments: prothrombin generation test and correction test, simple prothrombin generation correction test for hemophilia stereotypes have definite significance: can be corrected by normal barium sulfate adsorption plasma but not corrected by normal serum for hemophilia A. Hemophilia B is those that cannot be corrected by normal barium sulfate adsorbed plasma but can be corrected by normal serum. Hemophilia C can be corrected by both normal barium sulfate adsorbed plasma and normal serum. There are also many clinical blood disorders that have similar symptoms to hemophilia, which should be distinguished. For example, it should be distinguished from vascular pseudohemophilia, which is caused by deficiency or reduction of VIIIR, Ag, and VIIIR:WF, and may also be caused by reduced activity of VIII:C. Typical vascular pseudohemophilia has a family history of autosomal dominant inheritance, i.e., both men and women can get the disease, and both parents can inherit it. The clinical manifestations are mainly mucosal and subcutaneous bleeding, and a few joint and muscle bleeding, but there is usually no joint deformity, prolonged bleeding time or positive aspirin tolerance test, and reduced VIII:C, VIIIR:RCOF and VIIIR:Ag, which can help in the diagnosis and differential diagnosis. The cause of hemophilia is mostly genetic. Variant vascular pseudohemophilia can be inherited in an autosomal recessive manner, with no clinical manifestations in the parents, no genetic history, more severe bleeding symptoms, normal bleeding time, and one to several items of VIIIR:RCOF, but abnormal cross-immunoelectrophoresis of VIIIR:Ag, which can help in differentiation. Hemophilia is more common with type A, and bleeding symptoms are the main manifestation of the disease. For this kind of patients, there is no better medical treatment yet, and blood transfusion is the only way.