Global sagittal spinal imbalance leads to compensatory pelvic retroversion and femoral flexion that is far from economical standing posture. Recent reports showed spinal instrumentation surgery provided remarkable restoration of spinal alignment and better health-related quality of life (HRQOL) by adult spinal deformity surgery. However, there is a few previous reports about the impact of pelvic and lower extremity sagittal alignment on HRQOL by adult deformity surgery. Thus, we analyzed the effect of compensatory mechanism in adult spinal deformity surgery. The purpose of this study was to report radiological and clinical outcome with the patients' compensatory mechanism following adult deformity surgery.