To investigate the protective effect of cerebrospinal fluid (CSF) on the spinal cord in patients with scoliosis and evaluate its buffering effect during gravitational traction surgery and in daily life. This study aims to provide theoretical guidance for surgical planning and postoperative rehabilitation of scoliosis.Methods: A three-dimensional coupled spinal cord-CSF finite element model was established to simulate the biomechanical responses of the spine under two scenarios: gravitational traction surgery and daily life. Comparative analyses were conducted for scenarios with and without CSF, and the buffering effect of CSF was quantitatively assessed.Results: During gravitational traction surgery, CSF significantly reduced the stress and deformation of the spinal cord, with the stress in spinal cord white and gray matter decreasing by 65%-90% and deformation decreasing by 70%-95%. In the daily life scenario, CSF provided greater protective effects in lateral flexion and forward-backward flexion directions, with stress reductions of 60%-85%. However, in torsion, the buffering effect of CSF was relatively weaker, with stress reductions of only 10%-25%.Conclusion: CSF significantly reduces spinal cord stress and deformation during gravitational traction surgery and in daily life, lowering the risk of injury. This study provides a reference for the development of future spinal biomechanics models and offers important biomechanical evidence for the surgical planning and rehabilitation training of scoliosis. It also highlights the importance of maintaining CSF integrity during surgery.