Primary myelofibrosis, also known as myelofibrosis, is a myeloproliferative disorder caused by the proliferation of collagen in the hematopoietic tissue of the bone marrow, whose fibrous tissue severely affects hematopoietic function, the cause of which is unknown. The disease has varying degrees of myelofibroblastic tissue hyperplasia, occurring primarily in the spleen first, followed by extramedullary hematopoiesis in the liver and lymph nodes. The typical clinical presentation is juvenile erythrocytic and juvenile granulocytic anemia with a high number of teardrop-shaped red blood cells. Bone marrow aspiration often shows dry aspiration, the spleen is often markedly enlarged, and there is varying degrees of osteosclerosis. Patients need to be reminded to pay more attention and go to hospital for relevant examination if the following symptoms appear clinically, including gradual onset of fatigue and weakness, pale skin and mucous membrane, joint pain, fever, left upper abdominal discomfort, hepatosplenomegaly, and severe anemia and hemorrhage may appear in advanced stages, all of which need to be identified for the development of primary myelofibrosis.