Abstract: The finite element method was used to evaluate the biomechanical effects of artificial lumbar intervertebral disc replacement and intervertebral fusion. Based on the CT image data， a finite element model of lumbar segments L2~L5 was established， and two kinds of surgical models of artificial lumbar disc replacement and intervertebral fusion were established. The simulated physiological load was applied to the finite element model， and the intervertebral activity and facet joint stress of each segment of the two surgical models were calculated. The simulation results showed that artificial lumbar disc replacement has a significant motion preservation in the surgical segment compared with intervertebral fusion，but the range of motion(ROM)were 40.9% and 43.1% higher than that of the normal lumbar in extension and lateral bending， which may cause mild instability of the surgical segment. Artificial disc replacement improves the stress state of the small joints of the upper and lower adjacent segments， but the replacement segment will induce higher contact pressure of the small joints under torsional conditions.

Key words: artificial lumbar disc replacement, intervertebral fusion, biomechanics, finite element, degeneration