Objective: To explore the risk factors for perioperative blood loss in patients undergoing posterior spinal scoliosis correction surgery. Methods: Collect surgical anesthesia data of patients who underwent posterior spinal scoliosis correction surgery due to idiopathic scoliosis at the First Affiliated Hospital of Guangxi Medical University from 2013 to 2022. The study subjects were determined based on inclusion and exclusion criteria, and were grouped according to whether there was significant intraoperative blood loss and postoperative blood drainage, analyzing the risk factors for significant intraoperative blood loss and significant postoperative blood drainage. Results: A total of 293 patients were included in this study, with 99 cases (33.8%) experiencing significant intraoperative blood loss. Multifactorial logistic regression analysis showed that preoperative Cobb angle ≥53.5 degrees (OR：3.08,95% CI：1.74-5.44), operative time ≥184 minutes (OR：3.17,95% CI：1.67-6.02), and number of screws placed ≥18 (OR：3.32,95% CI：1.86-5.93) were independent risk factors for significant intraoperative blood loss. Patients in the significant intraoperative blood loss group had an increased rate of allogeneic blood transfusion intraoperatively and postoperatively (P 0.05). There were 174 cases (59.4%) with significant postoperative blood drainage, and multifactorial logistic regression analysis showed that BMI ≤16 kg/m2 (OR：2.72,95% CI：1.39-5.30), intraoperative autologous blood transfusion (OR：2.73,95% CI：1.47-5.07), and number of segments operated ≥10 (OR：2.49,95% CI：1.33-4.69) were independent risk factors for significant postoperative blood drainage. The group with significant postoperative blood drainage had a significantly increased rate of blood transfusion postoperatively (P 0.01). Conclusions: A large preoperative Cobb angle, long operative time, and a high number of screws placed are independent risk factors for significant intraoperative blood loss in patients undergoing spinal scoliosis correction surgery; while low preoperative BMI, intraoperative use of autologous blood transfusion with a blood recovery machine, and a high number of segments operated are independent risk factors for significant postoperative blood drainage.