BACKGROUND Oblique lateral interbody fusion (OLIF) is a new and minimally invasive surgery. This study aimed to compare the clinical efficacy and safety of oblique lateral interbody fusion with anterolateral screw fixation and with posterior percutaneous screw fixation in treating single-segment mild degenerative lumbar diseases. MATERIAL AND METHODS A retrospective analysis was performed on 51 patients with single-segment mild degenerative lumbar diseases who received OLIF from April 2017 to January 2020 in Hong Hui Hospital, Xi'an Jiao Tong University; 24 and 27 patients received OLIF with anterolateral screw fixation (OLIF+AF) and OLIF with posterior percutaneous screw fixation (OLIF+PF), respectively. Anesthesia time, operation time, intraoperative blood loss, intraoperative fluoroscopy number, hospital stay, postoperative complications, Visual Analog Scale (VAS) score, Oswestry Disability Index (ODI) score, anterior and posterior disc heights, foraminal height, and fusion rate of the 2 groups were compared to assess clinical and radiological outcomes. RESULTS Anesthesia time, operation time, intraoperative blood loss, number of intraoperative fluoroscopy, and VAS score in the OLIF+AF group were significantly better than those in the OLIF+PF group (P<0.05). There were no significant differences in ODI score, anterior and posterior disc heights, foraminal height, fusion rate, and incidence of complications between the 2 groups (P<0.05). CONCLUSIONS OLIF+AF in treating single-segment mild degenerative lumbar diseases produces a satisfactory clinical effect. Moreover, OLIF+AF does not invade the paraspinal muscle group, thereby reducing trauma, postoperative residual low back pain, operation time, bleeding, and frequency of fluoroscopy. Thus, OLIF+AF is a feasible treatment method for single-segment mild degenerative lumbar diseases.