Lung cancer is with the highest incidence rate and mortality among people over 60 years old in China. Postoperative pulmonary complications (PPCs) is the most common complication after pneumonectomy, which has a significant impact on the short-term and long-term prognosis of patients, and is even the primary risk factor leading to early postoperative death. High fraction of inspired oxygen (FiO2) is an independent risk factor for PPCs, but it is difficult to achieve oxygenation while avoiding hyperxemia during one lung ventilation (OLV). We will randomly divide patients who plan to undergo thoracoscopic pulmonary resection into two groups. During OLV, titration will be used to determine the optimal FiO2 for titration group while FiO2 of 80% will be used for mechanical ventilation for control group. The incidence of postoperative PPCs, hypoxia/hyperxemia, severity level of postoperative PPC, postoperative 30 day PPC, increased hospitalization costs, and prolonged hospital stay will be observed in both groups of patients.We will evaluate the effectiveness and safety of titrating inhaled oxygen concentration in lung protection during OLV.