Objective To investigate the biomechanical influence ofvertebroplasty using autosolidification calcium phosphate cement (CPC) on thoracolumbar osteoporotic fractures. Methods Four cadaver specimens with osteoporosiswere applied to make spine unit. There were 2 females and 2 males, whose average age was 69 years.All underwent flexion-axial loading to result in vertebral body fracture. Following reduction, the middle fractured vertebral body were strengthened by the method of vertebroplasty, using CPC. Before fracture and after vertebroplasty, all were conducted biomechanical test. Results After being packed- CPC to the space in the fractured vertebral body, the strength andstiffness in vertebroplastic group (2 285±34 N，427±10 N/mm) were significantly higher than that in osteoporotic group (1 954±46 N，349±18 N/mm) (Plt;0.05). The vertebral height changing in vertebroplastic group(5.35±0.60 mm) were significantly lower than that in osteoporotic group (5.60±0.70 mm) (Plt;0.05). And the fractured body increases its strength and stiffnessby 16.92% and 22.31% respectively in comparison with its initial situation. Conclusion After being injected CPC into bone trabecular interspaces, the fractured vertebral bodies can restore its strength and stiffness markedly.