Objective To investigate the feasibility and effectiveness of uni-portal non-coaxial spinal endoscopic surgery (UNSES) via a single incision for the treatment of adjacent two-segmental lumbar disc herniation (LDH). Methods A retrospective analysis was performed on 33 adjacent two-segmental LDH patients treated with single-incision UNSES between June 2023 and May 2025, including 18 males and 15 females, with a mean age of 55.7 years (range, 28-74 years) and a mean disease duration of 11.2 months (range, 3-36 months). There were 4 cases of L3, 4, L4, 5 herniation and 29 cases of L4, 5 and L5, S1 herniation. Pfirrmann grade of disc degeneration was grade 3 in 24 segments, grade 4 in 39 segments, and grade 5 in 3 segments. Perioperative indicators were recorded. The visual analogue scale (VAS) score and Oswestry Disability Index (ODI) were evaluated preoperatively and at 3 days, 3 and 6 months postoperatively. The modified MacNab criteria were used to assess patient satisfaction at last follow-up. Postoperative lumbar CT or MRI was applied to evaluate nerve root decompression. Lumbar lordosis angle and L3, 4, L4, 5, and L5, S1 segmental endplate angles on standing lateral X-ray films were measured to compare sagittal balance changes before operation and at last follow-up. Results The operation time was 70-126 minutes, with an average of 84.8 minutes; the incision length was 1.8-2.4 cm, with an average of 2.1 cm; the fluoroscopy frequency was 1-4 times, with an average of 2.2 times; and the hospital stay was 5-12 days, with an average of 7.6 days. All patients were followed up 6-24 months, with an average of 14.1 months. The incidence of complications was 6.1% (2/33), including 1 case of dural tear (<4 mm) required no suture and presented no cerebrospinal fluid leakage, and 1 case complete inferior articular process resection had no obvious low back pain during follow-up. No myeloid hypertension-like syndrome, nerve root injury, cerebrospinal fluid leakage, or intervertebral space infection occurred in other patients. VAS score of low back and leg pain and ODI at each time point after operation were lower than those before operation, and further decreased with time, and the differences between different time points were significant (P<0.05). According to the modified MacNab criteria, 19 cases were excellent, 10 cases were good, 4 cases were fair, and the excellent and good rate was 87.9%. Postoperative lumbar MRI showed that the herniated nucleus pulposus tissue had been removed in all patients, the cross-sectional area of the spinal canal was significantly increased, and the nerve root was not significantly compressed. At last follow-up, there was no significant difference in lumbar lordosis angle, L3, 4 endplate angle, L4, 5 endplate angle, and L5, S1 endplate angle when compared with those before operation (P>0.05). Conclusion Single-incision UNSES has the advantages of small trauma, high safety, flexible operation, and extensive decompression, which can effectively complete the removal of two adjacent segments herniated disc, and the effectiveness is satisfactory.