The classification of lymphoma is very complex and morphologically diverse, and differential diagnosis is sometimes very difficult. Generally, the diagnosis of lymphoma should be made from four aspects, as follows: 1. Observe whether the structure of lymph nodes is destroyed and whether there is infiltration of heterotypic lymphocytes in lymph nodes. If there is destruction of the lymph node structure and there is infiltration of heterotypic lymphocytes, lymphoma should be considered. However, there are lymphomas that do not occur in lymph nodes, and it is possible to determine whether they are lymphomas simply by looking at whether there is a consistent morphological heterogeneous lymphatic infiltrate. Overall, morphological changes are the basis for judging lymphoma; 2. The types of lymphoma are complex and sometimes highly consistent in morphology, which need to be analyzed with the help of immunohistochemistry; 3. If it is difficult to diagnose or treat, molecular pathological tests need to be added, for example, gene rearrangement can distinguish benign reactive lymphoid tissue hyperplasia or malignant lymphoma, and FISH test can distinguish whether it is a double-hit, or triple-hit B-cell For example, gene rearrangement can distinguish benign reactive lymphoid hyperplasia or malignant lymphoma, and FISH test can distinguish whether the lymphoma is a double-hit or triple-hit B-cell lymphoma, thus providing the basis for clinical treatment. 4. Lymphoblast lymphoma is generally more common in children, while follicular lymphoma is more common in the elderly. Therefore, close clinical relationship can prevent misdiagnosis and improve the accuracy of lymphoma diagnosis.