Abstract Objective To study the effect of T1-slope(T1S) on intervertebral mobility and disc stress after Zero-P operation.Methods Two patients with C5/6 disc herniation were selected as the research objects according to the preoperative T1S measured by lateral cervical X-ray . Preoperative spiral CT scanning was performed from C1 to T2 . Three dimensional models of cervical vertebrae and Zero-P were established in mimics 14.0, Geomagic studio 10.0 and Cero 3.0. Through HyperMesh 13.0, Abaqus6.14 ,the control model, low tilt model（T1S ≤ 18 ° ）and high tilt model （T1S > 18 °） cervical finite element models were established,to define the material parameters, boundary conditions, and calculate the intervertebral mobility and disc stress under the flexion, extension, lateral bending, rotation loads.Results (1) The finite element model from C1 to T2 established in this study contains 33683 nodes and 135746 elements, which had a high degree of similarity. The range of motion of each segment was in the normal range.(2) The compensatory activity of adjacent discs in low tilt model was significantly higher than that in high tilt model and control model. The motion range of C4/5 in the low tilt model and the high tilt model increased by 26.85% and 14.81% respectively compared with the control model, while the lateral bending and rotation range of motion were 10.53%, 8.51% and 17.02%, 12.28% respectively. The increase of C6/7 was less than that of C4/5.(3) The stress of adjacent segments of intervertebral disc in Zero-P models was significantly higher than that in control model (P < 0.01). The stress of C4/5, C5/6 fusion cage and C6/7 in low tilt model were significantly higher than that in high tilt model (P < 0.01). There was no significant difference in stress between the two models under lateral bending and rotating loads (P > 0.05).Conclusion The decrease of T1S and cervical curvature were the main factors leading to the increase of adjacent segment disc motion and cage stress after Zero-P fusion.