Objective To investigate the efficacy of low-dose inhaled nitric oxide (iNO) in the treatment of severe hypoxemia after Sun’s operation. Methods The clinical data of patients undergoing Sun’s operation for acute Type A aortic dissection in our hospital from January 2020 to June 2022 were retrospectively analyzed. Patients who received conventional treatment before November 2021 were enrolled as a control group. After November 2021, iNO was used in our hospital, and the patients who received iNO as an iNO group. The preoperative clinical baseline data, perioperative clinical data and oxygenation index were compared between the two groups. Results A total of 54 patients were included in the control group, including 45 males and 9 females, with an average age of 53.0±10.9 years. A total of 27 patients were included in the iNO group, including 21 males and 6 females, with an average age of 52.0±10.6 years. The preoperative body mass index of the two groups was greater than 25 kg/m2, white blood cell count, C-reactive protein were significantly higher than normal level, but there was no statistical difference between the groups (P＞0.05). There were no statistical differences in intraoperative data between the two groups (P＞0.05). The iNO group had significantly shorter duration of mechanical ventilation, postoperative ICU stay, and postoperative hospital stay than the control group (P<0.001). After 12 h of iNO treatment, hypoxic condition improved obviously, oxygenation indices in 12 h, 24 h, 36 h,48 h, 60 h and 72 h in the iNO group were significantly higher than those in the control group (P<0.05). Conclusion The treatment of severe hypoxemia after Sun’s surgery with low-dose of iNO is safe and effective, can significantly improve oxygenation function, and has significant advantages in shortening ventilator use time, postoperative ICU stay and postoperative hospital stay, but it is not significant in changing postoperative mortality.