Abstract: Objective To explore the effect of MI-TLIF under expansion channel combined with pedicle screw fixation on treatment of patients with lumbar degenerative scoliosis complicated with spinal stenosis.Methods A total of 51 patients with lumbar degenerative scoliosis complicated with spinal stenosis were selected and divided into observation group (n =28) and control group (n =23).The control group was treated with TLIF combined with pedicle screw fixation,and the observation group was treated with MI-TLIF and pedicle screw internal fixation under the expansion channel.Clinical efficacy and low back pain were compared between two groups.Results The incision length,intra-operative blood loss,postoperative drainage volume,postoperative time and hospital stay in the observation group were significantly better than those in the control group,and the operation time was significantly longer than the control group (P ＜ 0.05).The VAS score and ODI score of the observation group were significantly lower than those of the control group (P ＜ 0.05).The bone graft fusion rate after one year was 92.86％ in the observation group,which was slightly higher than 86.96％ in the control group (P ＞ 0.05).There were no serious complications in the two groups.Conclusion In the treatment of patients with lumbar degenerative scoliosis complicated with spinal stenosis,the clinical efficacy of MI-TLIF assisted with pedicle screw fixation under expansion channel is equivalent to traditional TLIF.