Objective: Recently, vertebroplasty and kyphoplasty are surgical options for themanagement of osteoporotic fractures. Kyphoplasty has the potential of restoring vertebral body height and providing a reversal of excessive kyphosis. Kyphoplasty generally showing less potential or extravertebral cement extravasation. Clinical peer-reviewed literature is available on techniques and applications which have also been reported. It remains unclear the reason of adjacent vertebral body fractures, because of the differences between kyphoplasty and vertebroplasty. Few computational models have been reported in the literature to evaluate the biomechanical behavior. Therefore, this study presents a validated two–functional spinal unit (FSU) T11–L1 finite element model with a simulated kyphoplasty augmentation in T12 to predict stresses and strains within the bone cement and bone of the treated and adjacent nontreated vertebral bodies. As a digital simulated analyse, this study adopt entity model, different with in vitro model. It can reflect human biological character, especially the simulation of ligament and disc prosthesis are more close to the real configuration. Simulations were conducted imposing a compression preload combined to a flexion/extension moment, a pure lateral bending moment and a pure torsion moment, and to quantify the stress levels in intervertebral discs, endplate, cancellous bone, cortical bone and in the bone of treated and adjacent vertebral bodies following kyphoplasty under clinically relevant loading conditions.Methods: Choosing a female patient following a kyphoplasty treatment and nontreatment, 68 years, 160cm, 55kg, without osteal abnormity and spinal monstrosity. Using the helix scan from top to bottom. Layer thickness was 0.6mm and space between two scans was 0mm. The extension included all the component of T11-L1 such as vertebrae, ligaments, discs. 789 pictures were obtained and 745 were applied for modeling. Datas were saved in CD which can be read and written. Applying C-basic program to test the divided images and pick up the boundary coordinate of T11-L1 osteal configuration and discs. Then the images were saved as single cloud files. To import these files to Geomagic software. The model went through“point phase”,“polygon phase”and“shape phase”, then made NURBS surface. The entity models were saved as IGES style. Next, files of IGES style were imported to Ansys 9.0. The vertebrae and discs were meshed using 10-node“brick”element. The endplates and annulus fibrosus were meshed as a system, but the nucleus was distinguished. In order to compare with the former studies, the inferior surface of L1 vertebral body was fully constrained. Pure moment loading of 300N.m was applied. Simulations were conducted imposing a compression preload combined to a flexion/extension moment, a pure lateral bending moment and a pure torsion moment, and to quantify the stress levels in intervertebral discs, endplate, cancellous bone, cortical bone and in the bone of treated and adjacent vertebral bodies following kyphoplasty under clinically relevant loading conditions.Results: Kyphoplasty restore vertebral body height and provide a reversal of excessive kyphosis, and the changes in stresses and strains in levels adjacent to a kyphoplasty-treated level are minimal. Adjacent nontreatedvertebral bodies do not undergo immediate biomechanical changes arising from kyphoplasty treatment However, stresses and strains in intervertebral discs are increasing.Conclusion: In the part of maintaining the stabilization of cervical spine, vertebrae, discs, joints, muscles and ligaments all take the important effects. Via the analyse of the DOF of the model. The results presented here suggest that adjacent nontreatedvertebral bodies do not undergo immediate biome- chanical changes arising from kyphoplasty treatment. Kyph- oplasty has restored vertebral body height. The effects of body adjacent to a kyphoplasty-treated level are minimal, but it could lead intervertebral discs to degenerate.