Objective To explore early effectiveness of unilateral biportal endoscopy (UBE) technique in the treatment of migrated lumbar intervertebral disc herniation. Methods  A retrospective analysis was conducted on 87 patients with migrated lumbar intervertebral disc herniation, who were treated with UBE technique between May 2021 and December 2022 and met the selection criteria. There were 55 males and 32 females, with an average age of 48.8 years (range, 29-74 years). The disease duration ranged from 2 to 23 months, with an average of 9.1 months. The surgical segments included 17 cases of L_{3, 4}, 32 cases of L_{4, 5}, and 38 cases of L₅, S₁. According to Lee’s classification criteria, there were 12 cases of type 1, 17 cases of type 2, 37 cases of type 3, and 21 cases of type 4. The operation time, length of hospital stay, and complications were recorded. The visual analogue scale (VAS) score was used to assess the degree of low back and leg pain before operaion and at 3 days, 3 months, 6 months, and 12 months after operation. The Oswestry disability index (ODI) was used to evaluate the lumbar spine function. At last follow-up, the modified MacNab criteria was used to evaluate the effectiveness. According to the preoperative migrated intervertebral disc classification, the patients were allocated into groups Ⅰ to Ⅳ. The differences in VAS score and ODI were compared. Results  All 87 patients successfully completed the operations. There was no nerve root injury, dural sac injury, or dural tear during operation. The operation time was (58.6±14.6) minutes and the length of hospital stay was (4.0±0.8) days. All incisions healed by first intention after operation. No symptomatic epidural hematoma occurred. All patients were followed up for 12 months. There were significant differences in VAS scores and ODI at each time point after operation when compared with those before operation (P<0.05). There were significant differences in VAS score at 3 days after operation when compared with that at 3, 6, and 12 months after operation (P<0.05). For ODI, except that there was no significant difference between 6 and 12 months after operation (P>0.05), there were significant differences between other time points after operation (P<0.05). At last follow-up, the effectiveness was rated as excellent in 66 cases, good in 13 cases, and fair in 8 cases according to the modified MacNab criteria, and the excellent and good rate was 90.8%. There was no intervertebral disc herniation recurred during follow-up period. There was no significant difference in VAS score and ODI among groups Ⅰ -Ⅳ before operation and at each time point after operation (P>0.05). Conclusion The UBE technique is safe and effective in the treatment of migrated lumbar intervertebral disc herniation, with a low complication rate and satisfactory early effectiveness.