Monoclonal lymphocytosis generally refers to monoclonal b-lymphocytosis, and some literature points out that the significance of monoclonal b-lymphocytosis is not known, and most of them are asymptomatic and can be monitored regularly without special treatment for the time being; a small number of them can develop into chronic lymphocytic leukemia, and then need to undergo treatments such as chemotherapy, targeted therapy or hematopoietic stem cell transplantation. Monoclonal b-lymphocytosis refers to the immunophenotype with chronic lymphocytic leukemia, but without lymph node enlargement, peripheral blood lymphocytes <5×10^9/L, bone marrow lymphocyte infiltration <30%. And the population survey found that >3.5% of the 40-year-old healthy people have monoclonal B lymphocytosis. If the condition is stable people can be regular observation, symptomatic treatment mainly. When the patient has fever, significant weight loss, fatigue, anemia, platelet decrease, giant spleen or pain in the splenic region, enlarged lymph nodes with local symptoms, increased white blood cells, etc., it should be actively treated. Treatment with chemotherapy (alkylating agents, purine analogs, etc.), targeted therapy (ibrutinib, etc.), or hematopoietic stem cell transplantation is required. Monoclonal Lymphocytosis requires regular hematology specialist follow-up and a treatment plan based on changes in the condition after evaluation by a physician.