Objective To explore the influencing factors of limb swelling after hip and knee arthroplasty in the elderly. Methods The clinical data of 170 elderly patients who underwent hip and knee arthroplasty in our hospital from March 2021 to March 2023 were retrospectively analyzed. The postoperative limb swelling was counted and divided into swelling group (n =75) and non-swelling group (n =95) according to the swelling condition. The general conditions (gender, age, body mass index, past medical history), operation-related factors [preoperative surgical risk assessment (ASA classification), anesthesia method, intraoperative blood loss, intraoperative tourniquet time, operation time, recovery time, postoperative anticoagulation method, postoperative healing, postoperative white blood cell index, postoperative hemoglobin index], postoperative complications (cerebral infarction, urinary tract infection, pulmonary infection, patellar dislocation, lower extremity venous thrombosis), psychological factors (postoperative anxiety level, postoperative depression level, postoperative self-efficacy) were compared between the two groups. Univariate and multivariate Logistic regression analysis equations were used to analyze the risk factors affecting postoperative limb swelling. Results Among 170 elderly patients undergoing hip and knee arthroplasty, the postoperative limb swelling rate was 44.12% (75/170). There were significant differences in age, body mass index, previous coagulation dysfunction,ASA classification, intraoperative tourniquet time, hemoglobin content, postoperative healing and postoperative lower extremity venous embolism between the swelling group and the non-swelling group (P<0.05). Binary Logistic regression analysis showed that age, body mass index, tourniquet time and hemoglobin were independent influencing factors of limb swelling after hip and knee arthroplasty in the elderly (P<0.05). Conclusion Advanced age, body mass index, intraoperative tourniquet time and hemoglobin level are independent risk factors for limb swelling in elderly patients undergoing hip and knee arthroplasty. Targeted measures can be taken to reduce the risk.