ObjectiveTo investigate the clinical value of prophylactic high-flow nasal cannula oxygen therapy (HFNC) in reducing postoperative pulmonary complication (PPC) in elderly patients with non-small cell lung cancer (NSCLC). Methods The clinical data of elderly patients (over 60 years) with NSCLC who underwent video-assisted thoracoscopic lobectomy or segmental resection at the Department of Thoracic Surgery, Fujian Provincial Hospital from January 2021 to March 2022 were retrospectively analyzed. According to whether receiving HFNC after surgery, they were divided into a conventional oxygen therapy (CO) group and a HFNC group. The CO group were matched with the HFNC group by the propensity score matching method at a ratio of 1 : 1. We compared PPC incidence, white blood cell (WBC) count, procalcitonin and C-reactive protein on postoperative day (POD) 1, 3 and 5 and postoperative hospital stay between the two groups. ResultsA total of 343 patients (165 males, 178 females, average age of 67.25±4.79 years) were enrolled, with 53 (15.45%) receiving HFNC. Before matching, there were statistical differences in gender, rate of combined chronic obstructive pulmonary disease, pathology type and TNM stage between the two groups (all P<0.05). There were 42 patients successfully matched in each of the two groups, with no statistical difference in baseline characteristics (P>0.05). After propensity score matching, the results showed that the PPC incidence in the HFNC group was lower than that in the CO group (23.81% vs. 45.23%, P=0.039). WBC count on POD 3 and 5 and procalcitonin level on POD 3 were less or lower in the HFNC group than those in the CO group [ (8.92±2.91)×109/L vs. (10.62±2.67)×109/L; (7.68±1.58)×109/L vs. (8.86±1.76)×109/L; 0.26 (0.25, 0.44) μg/L vs. 0.31 (0.25, 0.86) μg/L; all P<0.05]. There was no statistical difference in the other inflammatory indexes or the postoperative hospital stay between the two groups (P>0.05). Conclusion Prophylactic HFNC can reduce the PPC incidence and postoperative inflammatory indexes in elderly patients with NSCLC, but does not shorten the postoperative hospital stay.