In patient with loss of lumbar lordosis, lumbar lordosis restoration is very important to get a normal sagittal balance. It is difficult to know the ideal lumbar lordosis, because it is a individual-unique pattern and is influenced by numerous variables. To restore a more ideal lumbar lordosis, careful analysis and planning will be needed because incomplete restoration of lumbar lordosis may result in poor clinical outcomes and serious complications. Lumbar lordosis has strong relationship with pelvic orientation, so there are many reports about predictive equation of lumbar lordosis using pelvic parameters. Pelvic incidence is major determinant of pelvic orientation, therefore, influence on lumbar lordosis. So pelvic incidence is a useful value to determine the ideal lumbar lordosis, and we recommend that the degree of restoration of lumbar lordosis is just enough to pelvic incidence at least. And also, a close study and understanding of the numerous factors affecting lumbar lordosis was needed to effective lumbar lordosis restoration.