Objective Through finite element analysis, to study the influence of residual kyphosis after vertebroplasty on the stress of injured vertebra and adjacent vertebra ,to provide help for clinical prevention of refracture. Methods The elderly patients with wedge-shaped, collapsed and flattened L1 vertebral compression fractures were collected, the spiral CT images of the patients in Mimics 17.0 ,Geomagic Studio 10.0 and HyperMesh 13.0 were used to establish the finite element models of 15% (A model), 30% (B model) and 45% (C model) kyphosis deformities. The axial load and torque were added to the surface of the lower end plate of the L2 as the boundary conditions to simulate the flexion, extension and lateral rotation of the vertebral body. The mechanical calculation is carried out in abaqus6.14. Results ①The displacement of T12 / L1 and L1 / L2 in wedge-shaped group and collapse flattening group increased significantly compared with the control group, and the largest increase was in C model. ② Under the flexion and rotation load, the stress of T12 lower end plate and L2 upper end plate in collapse flattening group was significantly higher than that in wedge-shaped group and control group (P < 0.01). But under the extension load ,there was no significant difference (P > 0.05). ③ The stress of bone cement in three groups,the collapse flattening group>the wedge-shaped group> the control group ,there was significant difference (P < 0.01). There was no significant difference among A, B and C models in the collapse flattening group (P>0.05), while in the wedge-shaped group ,C model was significantly higher than that in the B model and A model (P<0.01). Conclusion The residual kyphosis in vertebroplasty would affect the stability of sagittal spine. The patients with wedge-shaped fracture with collapse flattening and wedge-shaped fracture should take active intervention methods to avoid the aggravation of refracture or kyphosis.