Objective To establish a model of cervical spondylosis in rats. Methods Sixty SD rats (four months old) were ran-domly divided into control, muscle imbalance and posterior column instability group, ten rats in each group. Then the degeneration of X-ray film and motion function were evaluated by oblique board test. Results After analyzed the cervical films of control groups, the nature curve still existed, vertebral clearance had no abnormal. No ostensis spurs or ossifies in Luschka joint and joint processes were found. But in mus-cle imbalance and posterior column instability groups, the nature curve was disappeared or stiff, vertebral clearance were stenosis, osteosis spur formed, ossify or sclerosis emerged in Lnschka joint and joint process. Compared with control group in oblique board test, the muscle force decreased in muscle imbalance and posterior column instability group. There were no statistic significant difference between 2 and 4 months of control group, and also no difference in muscle imbalance and posterior column instability group, but there were significant differ-ence in 2 and 4 months of muscle imbalance and posterior column group. Conclusion Not only cervical posterior column instability but also muscle imbalance could result in cervical spendylosis, both muscle force balance and posterior column were important factors in maintaining spine stability.