Objective The purpose of this study was to compare the functional and morphological changes in the cervical spine with protrusion of cervical disc (PCD) under different directions of traction. Methods MRI scanning was used to study the effect of different directions of traction on the movement of protrusive disc，compression index of spinal cord and changes of intervetebral space,as well as the cases with degeneration. Results　Differences were found in the effect of different directions of traction. Most significant partial reduction of the protrusive disc was experienced in flexion traction. Both flexion and extension traction caused significant decrease in the index of compression of spinal cord. Extension traction caused marked narrowing of the posterior intervertebral space in the group with decreased disc size,while no difference between the groups with and without decreased disc size when given flexion traction. There was no difference in the anterior intervertebral space between the two directions of traction. No morphological change was observed in cases with degeneration using either direction of traction. Conclusion PCD could caused the change in the fine morphology of normal vertebral joints. The traction direction should be chosen according to the condition of the individual case. The compression index could better reflect the nature of spinal cord injury than the size of the disc protrusion. Traction would not give much benefit in cases with degeneration.