The finite element model for human lumbar spinal L3-L4 is described by three-dimensional reconstruction method-marching cubes (MC). With some vital soft tissues on spine, such as anterior ligament, opisthodetic ligament, yellow ligament and fiber ring added, the complete three-dimensional finite element model of spine is rebuilt precisely. Then the finite element model is divided into mesh and the corresponding material properties of all parts are set. Finally, load and boundary conditions with different directions are defined to simulate the stress and displacement of normal model and intervertebral disc swelling degeneration model under different conditions. Which can provide biomechanical basis on the clinical diagnosis and treatment of intervertebral disc bulge and intervertebral disc protrusion by analyzing its biomechanical properties.