A new method based on the score of preoperative magnetic resonance images (MRI) was devised to evaluate cervical spondylotic myelopathy and predict the results of cervical laminoplasty. On T1- and T2-weighted sagittal MRI, the intervertebral disc spaces at each level from the axis to the first thoracic spine were examined as to whether the anterior or posterior subarachnoid space would be maintained or not, and for the presence or absence of spinal cord deformity. The data were divided into six grades and rated, and the total score for all sites was regarded as the preoperative MRI cumulative score. In conclusion, our method was highly reliable and useful for a preoperative evaluation and prediction of results after cervical laminoplasty for cervical spondylotic myelopathy.