Zhang xx,male ,41 years old,ossificationof the thoracic posterior longitude and the yellow ligament,the patient has pyramid sign below the pathological change flat before operation,and the muscle force of both lower extrimities declined,muscle tension raisedand walking unstable ,from MRI ,multiple thoracic posterior longitudinal ligament and yellow ligament oppressed the spinal cord because of ossification,On march 10^th 2009,the patient ,under general anesthesia ,had a operation of posterior whole laminectomy decompression fusion and fixation with screw-rod system,Using ‘Bow-chord’ principle to decrease the angle of the thoracic physiological kyphosis and the angle after ossification and indirectly solve the problem of the oppression from the frontage,after operation ,patient’s symptoms began to ease .At present ,patient almost returned to normal.