Invasive lung adenocarcinoma stage 1b can be treated with chemotherapy if there are indications for chemotherapy. Stage 1b invasive lung adenocarcinoma refers to the tumor diameter of 3~4 cm, without lymph node and distant organ metastasis, and belongs to early stage lung cancer. Currently, there is some controversy about whether patients with stage 1b invasive lung adenocarcinoma need to undergo postoperative chemotherapy, and there is no sufficient research to show that postoperative chemotherapy can bring survival benefit to patients with stage 1b invasive lung adenocarcinoma. It is generally recommended that patients with stage 1b invasive lung adenocarcinoma undergo postoperative chemotherapy only when there are indications for chemotherapy to avoid over-treatment. Indications for chemotherapy include patients with good physical strength, tolerable function of vital organs, patients with high-risk factors for recurrence, and vascular invasion detected by tumor pathology. Commonly used chemotherapeutic agents include cisplatin, gemcitabine, and pemetrexed. Chemotherapeutic drugs can cause adverse reactions such as hair loss, nausea, vomiting, bone marrow suppression, etc. Chemotherapeutic drugs should be used in strict compliance with medical advice. Therefore, patients with stage 1b invasive lung adenocarcinoma should go to the hospital in time after surgery, and decide whether to have chemotherapy under the doctor’s advice and guidance after comprehensive evaluation.