Although comprehensive geriatric assessment (CGA) has been used widely, its impact on adverse events in elderly patients has not been fully examined. The present study aimed to investigate the relationships between subcomponents of CGA and adverse events (AEs) in elderly patients undergoing posterior lumbar fusion surgery.A total of 242 eligible elderly patients enrolled. Our CGA included activities of daily living, instrumental activities of daily living, nutritional status, cardiac function, pulmonary function, renal function, frailty, cognition, anxiety, depression, delirium, chronic pain score, comorbidity and polypharmacy. Comprehensive complication index was used to summarize postoperative complications and its severity. Logistic regression was performed to determine the relationships between subcomponents of a CGA and postoperative AEs.Present study found that female were more vulnerable to have AEs. Postoperative major AEs were associated with delirium (odds ratio (OR): 4.302, 95% confidence interval (CI) 1.720-10.761, p = 0.002), nutritional status (OR: 3.030, 95%CI 1.218-7.541, p = 0.017), cognitive impairment (OR: 4.122, 95%CI 1.179-14.407, p = 0.027), Charlson comorbidity index (CCI) (OR: 4.800, 95%CI 1.852-12.440, p = 0.001) and severe dependent (OR: 3.772, 95%CI 1.116-9.841, p = 0.007). Further analysis showed that delirium (OR: 2.824, 95%CI 1.068-7.467, p = 0.036) and CCI (OR: 3.221, 95%CI 1.184-8.766, p = 0.022) were independently related to major AEs.These results indicate that preoperative screening preoperative delirium, cognitive, nutrition and CCI are essential to prevent postoperative major AEs of the surgical elderly.© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.