Stage 3 follicular lymphoma indicates that the patient has lymph node invasion on both sides of the diaphragm, accompanied by spleen invasion. Follicular lymphoma is a kind of non-Hodgkin’s lymphoma, which is a kind of tumor originated from B cells of lymphoid follicular growth centers, and clinically it is divided into 4 different stages, among which stage 3 indicates that the lymph nodes on both sides of the diaphragm of the patient have been invaded, and accompanied by the spleen and the extra-lymphoid node invasion. Stage 3 follicular lymphoma is mainly treated with radiotherapy, and can be treated with single drugs such as nitrogen mustard phenylbutyrate, cyclophosphamide, etc. It can also be treated with CHOP chemotherapy regimen for comprehensive treatment, but it is prone to recurrence in the later stage, and needs to be well rechecked. It is suggested that patients should consult the doctor in time and actively cooperate with the doctor to avoid delaying the condition.