Thrombocytosis is not necessarily leukemia, but can also be seen in primary thrombocythemia, chronic granulocytic leukemia, myelofibrosis, true erythrocytosis, iron-deficiency anemia, after splenectomy, tuberculosis infection, but also in some solid tumors and some drugs caused. 1. The main pathophysiological characteristic of leukemia is that abnormal blood cells (i.e. leukemia cells) proliferate in the bone marrow and other hematopoietic tissues, infiltrate various tissues, while normal hematopoietic function is inhibited, and the production of normal blood cells decreases, and produces the corresponding clinical manifestations, such as acute leukemia is often manifested as thrombocytopenia, and the chronic phase may be manifested as thrombocytosis. 2. Thrombocytosis is not necessarily a manifestation of leukemia, but can also be seen in the following diseases: (1) Malignant tumors: Thrombocytosis can occur in many kinds of malignant tumors, such as oral squamous cell carcinoma, lung cancer, gastric cancer, hepatocellular carcinoma, pancreatic cancer, colorectal cancer, malignant pleural mesothelial carcinoma and gynecological malignant tumors. (2) Pharmacological Thrombocytosis: It is found that drugs such as levofloxacin, cefodizime, hygromycin, imipenem cisplatin sodium, gemcitabine, methiothiazole, Avicenna capsule and so on, are all caused by Thrombocytosis. (3) Infection: Thrombocytosis can also be seen in bacterial, viral, mycoplasma infections, respiratory tract infections, bacteremia, toxemia can lead to increased destruction of platelets, platelet products of the compensatory increase. Thrombocytosis can also be seen in primary thrombocythemia, myelofibrosis, anemia, after splenectomy, true erythrocytosis and many other diseases, so the occurrence of thrombocytosis should be timely medical treatment, diagnosis and treatment.