[Objective] To investigate the surgical safety and clinical efficacy of unilateral biportal endoscopy (UBE) in the treatment of prolapse lumbar disc herniation(PLDH). [Methods] A total of 27 cases of PLDH treated with UBE from July 2020 to October 2021 were analyzed retrospectively. The visual analogue scale (VAS) for low back pain and leg pain respectively, JOA and oswestry disability index (ODI) were evaluated before operation, 3 months and last follow-up after operation. The modified MacNab criteria were used for evaluation of the clinical consequences. In term of radiographic evaluation, the spinal canal occupancy ratio, the intervertebral height of the surgical segment and lumbar lordosis angle were evaluated before operation, 3 months and last follow-up after operation. [Results] All 27 patients were successfully operated, and the operation time was 88.52 ± 12.84 minutes. The follow up lasted for 12-27 months. Complications included dural tears in 1 case, recurrence in 1 case. The postoperative VAS score and ODI score significantly decreased, whereas the JOA score significantly increased, and the results showed statistically significant differences (P<0.05). As time went, the VAS score and ODI score continued to decrease (P<0.05), while the JOA score continued to increase (P<0.05). According to the modified MacNab criteria, the final clinical outcome was the excellent and good rate of 96.3%. In term of radiographic evaluation, the spinal canal occupancy ratio after surgery significantly decreased (P<0.05), and there was no significant change in the intervertebral height of the surgical segment and lumbar lordosis angle (P>0.05). [Conclusion] UBE is a very safe and effective surgical technique, and achieves satisfactory clinical outcomes for prolapsed lumbar disc herniation.