Background The comprehensive geriatric assessment (CGA) has been proposed as a supplementary tool to reduce perioperative complications of geriatric patients, however there is no universally accepted standardization of CGA for orthopedic surgery. In this study, a novel CGA strategy was applied to evaluate the conditions of older patients undergoing orthopedic surgery from a broad view and to identify potential risk factors for postoperative complications. Methods A prospective cohort study was conducted from March 2019 to December 2020.The study enrolled patients (age > 75 years) for elective or confined orthopedic surgery. All patients were treated by a multidisciplinary team. A structured CGA was conducted to identify high-risk older patients and to facilitate coordinated multidisciplinary team care by a geriatric team. The basic patient characteristics, CGA results, postoperative complication and mortality rates were collected. Multivariate logistic regression analysis was used to identify risk factors for postoperative complications. Results A total of 214 patients with an age of 81.07 +/- 4.78 (range, 75-100) years were prospectively enrolled in this study. In total, 66 (30.8%) complications were registered, including one death from myocardial infarction (mortality rate, 0.5%). Poor Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) were accompanied by frailty, worse perioperative risk, pain, and nutritional status. Poor ADL was also associated with higher risks of falling, polypharmacy, and cardiac and respiration complications. Poor IADL was associated with a higher risk of cardiac and respiration complications. Higher stroke risk was accompanied by higher risks of cardiac complications, delirium, and hemorrhage. Worse American Society of Anesthesiologists (ASA) score was associated with worse ADL, IADL, frailty, and higher delirium risk. Multivariate logistic regression analysis showed that spinal fusion (odds ratio [OR], 0.73; 95% confidence interval [CI], 0.65 to 0.83; p = 0.0214), blood loss(OR, 1.68; 95% CI, 1.31 to 2.01; p = 0.0168), ADL (severe dysfunction or worse) (OR, 1.45; 95% CI, 1.16 to 1.81; p = 0.0413), IADL (serious dependence) (OR, 1.08; 95% CI, 1.33 to 1.63; p = 0.0436), renal function (chronic kidney disease (CKD) >= stage 3a) (OR, 2.01; 95% CI, 1.54 to 2.55; p = 0.0133), and malnutrition(OR, 2.11; 95% CI, 1.74 to 2.56; p = 0.0101) were independent risk factors for postoperative complications. Conclusion The CGA process reduces patient mortality and increases safety in older orthopedic surgery patients. Spinal fusion, blood loss, ADL (severe dysfunction or worse), IADL (serious dependence), renal function (CKD >= stage 3a) and nutrition mini nutritional assessment (MNA) (malnourished) were independent risk factors of postoperative complications following orthopaedic surgery in older patients.