To investigate the predictive factors of pain intensity during the first 48 hours after spinal correction and fusion operations for idiopathic scoliosis patients.A total of 290 scoliosis patients who underwent posterior spinal instrumentation and fusion operations were enrolled in this study. A standard surgical and analgesic method was implemented for all participants and pain intensity was evaluated at fixed times within 48 hours after the operation. Variables including demographics (age, sex, body mass index [BMI], patient sources), surgical variables (procedure, duration of operation), intraoperative variables (total transfusion, autologous transfusion, heterogeneous transfusion, fluid intake, use of preventive analgesia) were investigated.On univariate analysis, BMI, transfusion type and not implementing preventive analgesia were associated with more serious pain after a scoliosis correction operation. Multivariate analysis indicated that receiving heterogeneous transfusion and not implementing preventive analgesia were significant predictive factors for moderate and severe pain after the spinal correction operation.Our research indicated that the type of transfusion and preventive analgesia were significantly associated with the severity of pain. Body mass and patient sources should be considered before surgery. For patients under high risk of moderate and severe pain, the type of transfusion must be taken into consideration. This study explored the influencing factors of postoperative pain from a novel perspective, but some limitations existed in this present study, and future studies are needed.