Objective: To discuss the surgical technique, indication and the clinical effects of the Microscope Endoscopic Tubular Retractor System (METRx) for microendoscopic lumbar diskectomy with the preservation of the ligamentum flavum. Methods: Two hundred and eleven patients underwent single-segment METRx, with ligamentum flavum preservation in 65 patients (Group A), and without preservation in 146 patients (Group B). The two groups were compared clinically. All the patients suffered from low back pain and radicular syndrome to some extent, and the diagnosis was affirmed by CT and/or MRI. After exposed the interlaminar space regularly, the superior, inferior and lateral edge of the ligamentum flavum was released, the 3-sided dissociative ligament pacth was retracted medially during the spinal manipulation and restored anatomically after disc removal and the decompression of the nerve root. Results: According to the results of two groups, ligamentum flavum preservation technique was feasible under endoscope and helpful in reducing the scar formation in the spinal canal. Conclusions: The ligamentum flavum preservation technique enable the surgeons to preserve the natural barrier. It is feasible to perform METRx, and it is helpful in reducing the epidural fibrosis.