Abstract: Objective To investigate the influencing factors of postoperative complications following thoracoscopic lung resection in elderly patients and to provide a scientific basis for developing preoperative pre- habilitation strategies for high-risk elderly populations. Methods This retrospective study enrolled elderly pa- tients who underwent video-assisted thoracoscopic surgery (VATS) lung resection at the Department of Thoracic Surgery, Peking Union Medical College Hospital between April 2019 and July 2023. General clinical data, pulmonary function testing (PFT) parameters (including forced expiratory volume in 1 secondFEV₁%pred, forced vital capacityFVC%pred, and peak expiratory flowPEF%pred), cardiopulmonary exercise tes- ting (CPET) parameters (peak oxygen uptakepeak VO₂ and resting arterial oxygen saturationSpO₂, etc.), and postoperative complications were collected. Univariate analysis and multivariate Logistic regression were performed to identify independent risk factors for postoperative complications. Results Among 219 eligible patients, 44 developed postoperative complications (complication group), while 175 did not (non- complication group). Univariate analysis revealed that the complication group had higher body mass index (BMI), smoking rates, lobectomy rates, and prevalence of preexisting arrhythmias, along with lower FEV₁% pred, FVC%pred, PEF%pred, peak VO₂, and resting SpO₂ (all P<0.05). Multivariate Logistic regression identified lobectomy (OR=6.04, 95% CI:2.55-14.33), history of arrhythmia (OR=3.13, 95% CI:1.08-9.12), decreased FVC%pred (OR=1.04, 95% CI:1.01-1.06), and reduced peak VO₂ (OR=1.17, 95% CI:1.03-1.32) as independent risk factors for postoperative complications. Conclusions Lobectomy, preexisting arrhythmias, decreased FVC% pred, and reduced peak VO₂ are significantly associated with an elevated risk of postoperative complications in elderly patients undergoing VATS lung resec- tion. These findings underscore the importance of preoperative risk stratification and tailored prehabilitation strategies to optimize outcomes in this population.