As an effective way to reconstruct the spinal alignment, osteotomy has been widely used to reconstruct the sagittal alignment of spine and achieved significant results.In order to avoid the secondary sagittal disequilibrium caused by the inaccurate osteotomy angle, it is very important to make an appropriate operation plan before the operation and evaluate the osteotomy angle accurately.At present, scholars have proposed different targets for sagittal reconstruction of the spine with different patients and diseases.They also proposed various prediction methods of osteotomy angle according to different reconstruction standards and principles, as well as the selection of osteotomy sites and methods.In this paper, the preoperative evaluation of the osteotomy angle was reviewed in terms of the target of sagittal reconstruction, the prediction of osteotomy angle and the selection of osteotomy method and osteotomy site.