Objective: To study the imaging method of the brachial plexus roots inside the spinal canal using computed tomography (CT) cervical myelography at No.108 Military Central Hospital. Subject and method: The study was conducted on 81 patients with brachial plexus injury. Contrast agent was injected into the spinal subarachnoid space and a cervical myelography was carried out on 16- and 320-detector row a scanners. All patients had diagnosis and treatment at No.108 Military Central Hospital, from July 2013 to December 2014. Result: Through this study, the authors realized: (1) a cervical myelography is indicated for patients with clinically suspected brachial plexus root injury but the lesions were not shown on MRI, for the patients with metal implants or those require early surgery. (2) Contrast agent used was Omnipaque (8 ml) mixed with saline or distilled water (2 ml), injected into the subarachnoid space of the lumbar spine at the levels of L2-3, L3-4 or L4-5. Patient then lied down supine with the lower head, in order to push the contrast agent to the cervical spine. (3) a scan of cervical spine was taken under the spiral protocol, slice thickness of 0.5 mm. Post-scanning images then were reconstructed on a curved plane in the coronal position or along the path of each lumbar or dorsal root. Conclusion: a cervical myelography is the diagnostic method that gives high-quality images of the brachial plexus nerve roots inside the spinal canal.