Stage 3A lung adenocarcinoma belongs to middle and advanced lung adenocarcinoma. Targeted therapy is often used as postoperative adjuvant therapy for patients with corresponding gene mutation, and the effective rate is about 70%-80%. Lung adenocarcinoma belongs to non-small cell lung cancer, stage 3A lung adenocarcinoma belongs to intermediate and advanced stage, radical surgery is preferred for patients with surgical indications, and postoperative adjuvant chemotherapy is usually needed, with platinum as the commonly used drugs, and if there is an EGFR mutation, targeting drugs such as ositinib can be used as adjuvant therapy. Stage 3A lung adenocarcinoma that is not suitable for surgery is usually treated with simultaneous radical radiotherapy or sequential radiotherapy. It is suggested that patients should choose appropriate treatment according to their own conditions under the guidance of doctors to avoid delaying their conditions.