PURPOSE: This study aims to determine the learning curve for lumbar discectomy and nerve root decompression using the unilateral biportal endoscopic (UBE) technique on fresh frozen cadavers through linear regression and cumulative sum (CUSUM) analyses. METHODS: The analysis was conducted on three spine surgeons without UBE experience. They performed lumbar discectomy using the unilateral endoscopic technique on fresh frozen cadavers. Each physician performed operations on 40 lumbar spine segments, recording the time it took each physician to complete a segment of lumbar discectomy by UBE. The learning curve was assessed by linear regression and CUSUM analysis using SPSS 27.0 software and GraphPad Prism 8.0 software. RESULTS: According to the CUSUM analysis of the learning curve, the number of segments required to complete the learning phase for the three surgeons was 20, 16, and 20, respectively. With the increased number of operated segments, the operation time for each lumbar vertebral segment gradually decreased and stabilized. CONCLUSIONS: In our study, spine surgeons without experience in UBE require 20 segments of surgery to overcome the UBE learning curve. Additionally, fresh frozen cadavers can effectively simulate real surgeries. Whenever possible, we should reasonably use fresh frozen cadavers for early UBE training of doctors, thereby better protecting the health and safety of patients.