Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue is an extranodal lymphoma composed of small B cells and is a malignant clonal tumor. This lymphoma is most common in middle-aged and elderly people, and the lesion tissue is infiltrated mainly with marginal zone cells, monocytes, small lymphocytes, and immunoblasts, and plasma cell differentiation may occur in some lymphomas. The lymphomas are mainly localized, including tissues of the gastrointestinal tract, thyroid, skin, and respiratory tract, and in severe cases they may be multiple and involve the bone marrow. Treatment for lymphoma of the extranodal marginal zone of mucosa-associated lymphoid tissue is based on chemotherapy, which is used to improve the patient’s condition by inhibiting the growth of the lymphoma. However, chemotherapy is not curative, and patients may choose to undergo hematopoietic stem cell transplantation in order to achieve the clinical standard of cure.