Objective To compare the effectiveness between unilateral biportal endoscopic lumbar interbody fusion (ULIF) and endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) in treatment of lumbar spinal stenosis combined with intervertebral disc herniation. Methods A clinical data of 64 patients with lumbar spinal stenosis and intervertebral disc herniation, who were admitted between April 2020 and November 2021 and met the selection criteria, was retrospectively analyzed. Among them, 30 patients were treated with ULIF (ULIF group) and 34 patients with Endo-TLIF (Endo-TLIF group). There was no significant difference in baseline data such as gender, age, disease duration, lesion segment, preoperative visual analogue scale (VAS) score of low back pain and leg pain, Oswestry disability index (ODI), spinal canal area, and intervertebral space height between the two groups (P>0.05). The operation time, intraoperative blood loss, hospital stays, and postoperative complications were compared between the two groups, as well as the VAS scores of low back pain and leg pain, ODI, and imaging measurement indicators (spinal canal area, intervertebral bone graft area, intervertebral space height, and degree of intervertebral fusion according to modified Brantigan score). Results Compared with the Endo-TLIF group, the ULIF group had shorter operation time, but had more intraoperative blood loss and longer hospital stays, with significant differences (P<0.05). The cerebrospinal fluid leakage occurred in 2 cases of Endo-TLIF group and 1 case of ULIF group, and no other complication occurred. There was no significant difference in the incidence of complications between the two groups (P>0.05). All patients in the two groups were followed up 12 months. The VAS scores of lower back pain and leg pain and ODI in the two groups significantly improved when compared with those before operation (P<0.05), and there was no significant difference between different time points after operation (P>0.05). And there was no significant difference between the two groups at each time point after operation (P>0.05). Imaging examination showed that there was no significant difference between the two groups in the change of spinal canal area, the change of intervertebral space height, and intervertebral fusion rate at 6 and 12 months (P>0.05). The intervertebral bone graft area in the ULIF group was significantly larger than that in the Endo-TLIF group (P<0.05). ConclusionFor the patients with lumbar spinal stenosis combined with intervertebral disc herniation, ULIF not only achieves similar effectiveness as Endo-TLIF, but also has advantages such as higher decompression efficiency, flexible surgical instrument operation, more thorough intraoperative intervertebral space management, and shorter operation time.