To prospectively compare the clinical efficacy and radiographic outcomes between interlaminar percutaneous endoscopic lumbar decompression(IL-PELD) and transforaminar percutaneous endoscopic lumbar decompression(TF-PELD) in the treatment of single-segment lumbar lateral recess stenosis. From April 2018 to July 2021, 85 patients with single-segment lumbar lateral recess stenosis underment percutaneous endoscopic lumbar decompression.There were 44 males and 41 females, aged from 49 to 81 years old with an average of (65.5±8.3) years old, duration of lumbar lateral recess stenosis ranging from 3 to 83 months with an average of (26.7±16.5) months. They were divided into IL-PELD group and TF-PELD group according to the different operation methods. There were 47 patients in the IL-PELD group, including 28 males and 19 females aged from 50 to 80 yeaes old with an average age was (66.7±9.3) years old. The disease duration ranged from 3 to 65 months with an average of (25.7±15.0) months. There were 38 patients in the TF-PELD group, including 16 males and 22 females, aged from 51 to 78 years old with an average of(64.1±7.6) years old. The disease duration ranged from 4 to 73 months with an average of (27.9±18.3) months The operation time, intraoperative blood loss, intraoperative fluoroscopy, hospitalization day and complications of the two groups were recorded. Visual analogue scale (VAS) to evaluate low back pain and lower limb pain, Oswestry disability index(ODI) to evaluate lumbar function in preoperative and postoperative period(1month, 6 months and last follow-up)were recorded. the sagittal diameter of the lateral recess of the responsible intervertebral space in preoperative and 1 week after the operation were recorded. The operation was successfully completed in both groups without serious complications such as vascular injury, dural sac tear and nerve injury. The operation time in IL-PED group(69.3±19.3)min was significantly longer than that in TF-PELD group(57.5±14.5)min (P<0.05). There was no significant difference in the intraoperative blood loss between the two groups (P>0.05). The number of intraoperative fluoroscopy in TF-PELD group (8.8±2.6)times was significantly higher than that in IL-PED group(4.8±1.2)times (P<0.05). The hospitalization days of the two groups were not statistically significant (P>0.05). VAS for low back and lower extremity pain and ODI were (5.1±2.2), (6.9±1.3) scores and (71.4±12.6) % in IL-PELD group, and (4.7±1.8), (6.9±1.3) scores and (68.4±13.9)% in TF-PELD group. In the IL-PELD group, the VAS of low back pain was (2.4±1.5), (1.6±0.8), (1.4±0.9) scores, and the VAS of lower extremity pain was (3.0±1.2), (1.6±0.7), (1.5±1.0) scores, ODI was (32.6±11.9) %, (17.4±6.5) %, (19.3±9.3)%;In TF-PELD group, the VAS of low back pain was (2.6±1.4), (1.5±0.6), (1.4±1.0) scores, and the VAS of lower extremity pain was (2.8±1.2), (1.6±0.6), (1.5±1.2) scores, The ODI was (32.0±11.2) %, (15.0±6.1) %, and (20.0±11.3) %. The VAS and ODI of the two groups at each time point after operation were significantly improved compared with those before operation (P<0.05), but there was no statistically significant difference between the groups (P>0.05), and there was no statistically significant difference in the interaction between different time points and groups (P>0.05). At 1 week after operation, the sagittal diameter of lateral recess in both groups was significantly increased compared with that before operation (P<0.05), but there was no significant difference between the two groups at each time point (P>0.05). According to the modified Macnab criteria, IL-PELD group was rated as excellent in 24 cases, good in 19 cases and fair in 4 cases. In TF-PELD group the results were excellent in 19 cases, good in 15 cases, fair in 3 cases and poor in 1 case. There was no significant difference between the two groups (P>0.05). IL-PELD and TF-PELD can expand the lateral recess in the treatment of single level lumbar lateral recess stenosis, and have achieved good clinical effects.