Objective To analyze the effectiveness and safety of robot-assisted percutaneous endoscopic posterior/transforaminal lumbar interbody fusion (RPE-P/TLIF) in the treatment of lumbar spinal stenosis with instability. Methods A single-center prospective study from September 2018 to April 2022, patients with lumbar spinal stenosis and instability who met the inclusion and exclusion criteria were treated with RPE-P/TLIF. Pain visual analog scale (VAS) was used to evaluate the degree of low back pain and lower limb pain before operation, 1 month, 6 months, 1 year after operation and at the final follow-up, and the Oswestry disability index (ODI) was used to evaluate the degree of lumbar spinal function. At the last follow-up, MacNab criteria were used to evaluate the clinical efficacy. Imaging evaluation included the measurement of intervertebral space height, lumbar physiological curvature, fusion rate and pedicle screw accuracy by preoperative and lateral X-ray films.