According to the physiological characteristics of lumbar vertebrae in Chinese, we designed and made a lumbar vertebral fusion cage of titanium and then engaged in its biomechanical test. T12-S1 of lumbar vertebrae from 18 fresh dead bodies were used. We measured the stress relaxation and the creep effects of the normal group (T12-S1 of intact lumbar vertebrae), the control group 1(simulating operation of excising intervertebral disc and planting bone on the back route) and the control group 2(simulating operation of excising intervertebral disc and inserting fusion cage). The data and stress, strain-time curves under the condition of constant stress and strain were obtained. Regression analysis yielded the reduced stress relaxation and creep functions. Finally, we analyzed and discussed the effects of the operation of excising intervertebral disc and planting bone on the back route and the operation of excising intervertebral disc and inserting fusion cage on the stability of spine.