ObjectiveTo systematically evaluate the risk factors for postoperative pulmonary infection in patients with lung cancer (PPILC), and to provide a theoretical reference for clinicians to prevent the occurrence of PPILC. Methods The databases of CNKI, Wanfang data, VIP, CBM, PubMed, EMbase and The Cochrane Library were searched by computer to collect researches on the risk factors for PPILC. The search period was from 2012 to 2021. Two clinicians independently screened literature and extracted data and assessed studies for risk of bias, cross-checked and agreed. Meta-analysis was performed using RevMan 5.3 software. Results A total of 25 studies were included, including 20 case-control studies, 1 cohort study, and 4 cross-sectional studies, covering 15 129 patients. Twenty case-control studies and 1 cohort study had Newcastle-Ottawa Scale (NOS) scores≥6 points, and 4 cross-sectional studies had the Agency for Health Care Quality and Research (AHRQ) scale scores≥6 points. The results of meta-analysis showed that the risk factors for PPILC included: (1) 4 patient's own factors: age≥60 years, male, smoking history, smoking index≥400; (2) 7 preoperative factors: suffering from diabetes, chronic heart failure and chronic obstructive pulmonary disease, the ratio of forced expiratory volume in 1 second to forced expiratory volume<70%, the ratio of forced expiratory volume in 1 second to the predicted value, preoperative airway colonization, non-standard use of prophylactic antibiotics before surgery; (3) 3 intraoperative factors: operation time≥3 h, thoracotomy, the number of resected lobe≥2; (4) 3 postoperative factors: postoperative pain, postoperative mechanical ventilation≥12 h, postoperative invasive operation. Large number of preoperative lymphocyte, intraoperative systematic lymph node dissection, TNM stage Ⅰ and Ⅱ, and enhanced recovery after surgery were protective factors for PPILC. Conclusion The current research evidence shows that multiple factors are associated with the risk of PPILC. However, considering the influence of the quality and quantity of the included literature, the results of this study urgently need to be further verified by more high-quality clinical studies.