Background: In video-assisted thoracoscopic surgery (VATS), intubated anesthesia may affect cerebral oxygen balance and postoperative cognitive dysfunction (POCD). To avoid complications associated with intubated anesthesia, tubeless strategies have been proposed in recent years, but its effect on cerebral oxygen balance and POCD is still unclear. This prospective study compared the cerebral oxygen saturation and the incidence of POCD in patients undergoing VATS anesthetized with tubeless anesthesia vs. intubated anesthesia.Methods: A total of 60 patients with American Society of Anesthesiologists Standard (ASA) grade I-II who planned to undergo VATS at The First People's Hospital of Yunnan Province between May and October 2021 were selected and divided into non-intubated spontaneous ventilation group (SV group) or intubated mechanical ventilation group (MV group) by random number method. The primary outcome included the incidence of POCD and Mini-Mental State Examination (MMSE) on the 1st before operation and the 4th, 7th, 14th, and 30th day postoperatively, and cerebral oxygen saturation during surgery. Other outcomes of interest include respiratory and hemodynamic parameters, serum concentration of cognitive function related proteins [S10013, interleukin (IL)-6, IL-113, and tumor necrosis factor alpha (TNF alpha)], inflammatory cell counts, perioperative adverse events (arrhythmia, hypoxemia, asphyxia, etc.), postoperative pain scores, etc.Results: The incidence of hypercapnia in the SV group was significantly higher than in the MV group (P<0.001). Cerebral oxygen saturation at intraoperative was significantly higher than that in MV group (P<0.01). There was no significant difference in the incidence of POCD and the expression of cognitive function related proteins between the two groups (P>0.05). Leukocyte and neutrophil counts were significantly higher in the MV group after operation (P<0.05), whilst compared to the MV group, the SV group showed shorter postoperative recovery time, rest time before the first out of bed activity, chest tube duration, as well as less drainage volume of the chest tube and postoperative sore throat rarely occurred (P<0.05). Conclusions: Tubeless VATS can increase the incidence of hypercapnia and intraoperative cerebral oxygen saturation, but has no statistically significant difference in the incidence of POCD. In addition, tubeless anesthesia reduces systemic inflammatory, promotes the early postoperative mobilization, and accelerates the postoperative rehabilitation of patients.Trial Registration: Chinese Clinical Trial Registry ChiCTR2100042381.