[Objective] To study the efficacy of unilateral MIS-TLIF and traditional TLIF in the treatment of degenerative lumbar spinal stenosis. [Methods] A retrospective analysis was performed on 104 patients with degenerative lumbar spinal stenosis who were operated on for 6 years from January 2017 to 2018, of which 50 were treated with unilateral mis-tlif and 54 were treated with traditional TLIF. The operative time, bleeding volume and postoperative drainage volume of the two groups were compared. VAS and ODI scores of the two groups were compared before, after and at the last follow-up, and the dorsal disc height, ventral disc height, intervertebral foramen height, anteroposterior diameter of intervertebral foramen, area of intervertebral foramen and anterior convex Angle of intervertebral foramen were measured. [Results] The operation time, intraoperative blood loss and postoperative drainage volume in the observation group were all lower than those in the control group, with significant differences between groups (P<0.05). The mean follow-up time was (26.42±4.23) months in the observation group and (27.42±5.21) months in the control group. At the last follow-up, the intervertebral fusion rate of the two groups was 100%, and the fusion device and internal fixation position were good. VAS and ODI scores were significantly lower in the two groups after surgery and at the last follow-up than before treatment (P<0.05). VAS score and ODI score were significantly lower in the observation group than in the control group (P<0.05). During the postoperative and final follow-up, the dorsal height of the disc, ventral height of the disc, height of the intervertebral foramen, area of the intervertebral foramen and anterior convex Angle of the intervertebral foramen of the two groups of patients increased significantly compared with that before the operation, with statistically significant differences (P<0.05), and the observation group was significantly higher than the control group (P<0.05). After the last follow-up and after surgery, there were no significant differences between the two groups in dorsal disc height, ventral disc height, intervertebral foramen height, intervertebral foramen area and anterior convex Angle (P>0.05). There was no significant difference in the diameter of the intervertebral foramina between the two groups (P>0.05), and no significant difference between the two groups (P>0.05). [Conclusion] Both unilateral mis-tlif and traditional TLIF can achieve better clinical efficacy in the treatment of degenerative lumbar spinal stenosis, with higher vertebral fusion rate. However, unilateral mis-tlif has more obvious advantages in operation time, blood loss, surgical trauma, postoperative recovery speed and other aspects.