The objective of this study was to evaluate the significance of preoperative heart rate variability (HRV) as a surrogate marker for vagus nerve activity in predicting the incidence of postoperative pneumonia (POP) and lung function recovery in patients undergoing lung cancer surgery.A prospective observational study was conducted at a single center. Patients were categorized into two groups: the POP group, which included those who developed pneumonia post-surgery, and the non-POP group, comprising patients who did not experience POP.A total of 257 subjects met the inclusion criteria and were ultimately included in the study. 33 patients presented POP, accounting for 12.8% (33/257) of the patients. Logistic regression revealed that preRMSSD (OR: 0.812, 95%CI: 0.720-0.912, P = 0.001) and preHFP (OR: 0.990, 95%CI: 0.983-0.996, P = 0.002) were the independent factors for POP; receiver operating characteristic curve (ROC) analysis for predicting the occurrence of the POP revealed that the combination of BMI, preHFP and preRMSSD showed the positive diagnostic accuracy (AUC: 0.867, P < 0.001). A logistic regression analysis showed that HRV indicators including preRMSSD (OR: 0.937, 95%CI: 0.892-0.985, P = 0.010) and preHFP (OR: 0.995, 95%CI: 0.992-0.998, P = 0.001) were independent factors for well-recovery in FEV1% within postoperative 30 days. Similar results can be found in well-recovery in FVC% or DLCO%.These findings provided compelling evidence supporting the utility of HRV indicators in predicting both POP and postoperative lung function recovery among surgical lung cancer patients.ChiCTR2400085997, registered in 24/06/2024.© 2025. The Author(s).