Objective To simulate the cervical rotatory manipulation (CRM) in left/right lateral bending position by using the three-dimensional finite element, so as to investigate the effect of lateral bonding position on the displacement and intra-stress of cervical disc when performing CRM. Methods With MimieslO.Ol , Geomagic Studio, and Solidworks 14.0 software, a three-dimensional finite element model of C5-6 was developed from the CT scan images of a 25-year-old normal adult female. The model was imported into Ansys Workbench 14.5 to verify and simulate the CRM. The CRM was decomposed by prineipium of manipulation in left/right lateral flexion and rotated to the right side. The parameter of mechanics was analyzed with the finite element system. The change of displacement and intra-stress distribution in cervical disc simultaneously were displayed during simulating the manipulation. Results In left/right lateral bending position and rotated to the right side, the posterior part of the left side of cervical disc was all retracted. And the displacement was toward anterior, left lateral flexion (0.93 mm) was smaller than the right lateral flexion (1.12 mm). The intra-stress of cervical disc wen: focused on the posterior part of the right side and the left side in left/right lateral flexion, respectively, and the maximum strews of left lateral bending (7. 00 MPa) was smaller than that of the right lateral bending (8. 19 MPa). Conclusion When the cervical vertebra is in the left lateral bending position and mtates to the right side, the effects on the displacement and intra-stress are smaller than that of the right lateral bending position. Therefore, the left lateral bending position is more likely to protect the left side of cervical disc. When we treat cervical spondylotic radiculopathy with CRM, should let the patients rotate to the contralateral side with lateral flexion to the ipsilateral side. In this way, it can alleviate the symptom, and reduce the risk of secondary injury to the cervical disc of ipsilateral side at the same time. [ABSTRACT FROM AUTHOR]