Hemorrhage is the main clinical manifestation of hemophilia A. Patients have a lifelong tendency to bleed spontaneously, after minor injuries and surgery for a long time, and heavy cases may develop both after birth, while light cases develop a little later. 1. Skin and mucous membrane bleeding: Because the subcutaneous tissue, gums, tongue, oral mucosa and other parts are easily injured, they are the most frequent sites of bleeding. 2. Joint hemorrhage: Joint hemorrhage is a common clinical manifestation in patients with hemophilia A. It often occurs after trauma/walking for too long or exercise, causing synovial hemorrhage, mostly in the knee joint, followed by the ankle, hip, elbow, shoulder and wrist joints. 3. Muscle hemorrhage and hematoma: It often occurs in patients with hemophilia A. It mostly occurs after trauma/muscle activity for too long, mostly in muscles that have been exerted. 4. Hematuria: Patients with hemophilia A may develop microscopic hematoma. Patients with hemophilia A may have microscopic or visual hematuria, mostly without pain and without history of trauma, but with symptoms of renal colic if there is ureteral blood clot formation. 5. Pseudotumor (hemophilic hematocyst): Hematoma can occur in any part, mostly in the thigh, pelvis, calf, foot, arm and hand, and sometimes in the eye. 6. Bleeding after trauma or surgery: Various degrees of trauma, minor surgery Bleeding from other sites: Gastrointestinal bleeding can be manifested as vomiting blood, black stool, bloody stool or abdominal pain, and most patients have primary lesions such as gastric and duodenal ulcers; hemoptysis is mostly associated with primary lesions such as tuberculosis and bronchiectasis; sublingual hematoma can cause displacement of the tongue, and if the hematoma progresses to the neck, it often causes respiratory distress; intracranial hemorrhage is often the cause of death in patients with hemophilia.