Abstract: [Objective] To compare the safety and efficacy of posterior decompressive pedicle fixation in elderly patients with degenerative scoliosis (DS).[Methods] In a retrospective analysis of DS patients in our hospital, the long segment group underwent long segment fusion (58 patients) and the short segment group underwent short segment fusion (54 patients).The outcome measures included perioperative conditions, follow-up indicators, and imaging assessments.[Results] The perioperative indexes of the short segment group were all significantly lower than those of the long segment group (P < 0.05), and the patients of the short segment group had a significantly lower incidence of adverse effects than those of the long segment group (P < 0.05).All clinical and radiographic measures improved significantly in both groups, with lower back pain, lower extremity pain and functional scores in the long segment group significantly better than those in the short segment group (P < 0.05) and with the long segment group significantly better than those in the short segment group (P < 0.05).[Conclusion] Short segment decompressive fixation has a low incidence of surgical trauma and adverse effects, while long segment decompressive fixation can effectively restore the physiological function of the spine, and promote the improvement of radiographic indicators; it is suggested that flexible selection is based on the actual condition of patients.