Objective To explore the fixed-effects of the treatment using transarticular screw joint lateral mass screw unilateral bi-direction fixation through posterior midline approach.Methods 16 patients,12 patients with traumatic fracture-dislocation and 4 patients with cervical disc herniation with spinal stenosis,were treated with transarticular screw(caudad) joint lateral mass screw (cephalad)unilateral bi-direction fixation in the posterior cervical.Results 32 transarticular screws were implanted,including C4-5 8 pieces,C5-6 12 pieces,C6-7 12 pieces;36 lateral mass screws were implanted,including C2 13 pieces,C3 14 pieces,C4 9 pieces.All screws were successfully implanted in operation,without injuries and other complications in vertebral artery,nerve root and spinal cord.16patients were followed up for averaged 18 months ( 10 - 30 months).Surgical incisions reduced by half than traditional ,fusion time were 2.0 to 4.5 months for an average of 3.1 months.Conclusions When through theposterior fixed cervical spine,used transarticular screw joint lateral mass screw unilateral bi-direction fixation,fixed simply and reliably,reduced internal fixation materials for implantation,reduced operative time,increased bone bed area,the bone fusion rate was high,reduced the length of surgical incision,reduced the blood vessels,nerve root injury risk ,reduced complications such as axial symptoms ,saved medical expenses,achieved good results.