Halo body jacket provides a excellent method of immobilization in unstable cervical spine such as fracture, dislocation, fracture-dislocation, tuberculosis, neurofibromatosis, congenitsal anomalies of the dens. With or with aiding of halo body jacket, we could treated the various unstable cervical spine. The stability of cervical spine can be maintained with halo body jacket. The author's applicated halo body jacket for 22 cases of unstable cervical spine. 1. The application was simple and the control is easy in any plane to achieve stablilty for unstable cervical spine. 2. The fracture dislocation of cervical spine was reduced by halo ring traction and the reduction position was maintained during operation and until bone and soft tissue healing. 3. Early ambulation was possible, so reduce the complcation due to prolongedd bed rest. 4. During operation, it provided a safe position of the patient with ease, and didnot aggravated the neurological status. 5. Provided a good operation fileds and easy taking a grafted bone from ilum than halo body cast.