• Patient aged 20-79 years old, both male or female;

• Tumor size \<= 2cm on preoperative CT scan;

• Peripheral solitary nodule or the associated lesion is MIA or less invasive lesion;

• Preoperative CT indicated that the nodules were non-pure glass nodules (consolidation to tumor ratio \>= 0.25);

• Intraoperative frozen section confirmed invasive lung adenocarcinoma with micropapillary and solid subtype negative (\<= 5%);

• Intraoperative frozen section indicated the resection margins was free of tumor cells;

• Lung function could withstand both lung segmentectomy and lobectomy (FEV1 \> 1.5L or FEV1% \>= 60%);

• Eastern Cooperative Oncology Group, 0 to 2;

• Volunteer to participate the trial and sign the informed consent, able to comply with the follow-up plan and other program requirements.