Abstract: Objective To investigate the autophagic effe ct of Schwann cells in the process of rat sciatic nerve regeneration.Methods Wal lerian degeneration model was established by transecting the rat sciatic nerve. Samples from the distal stump were obtained 0, 0.5, 1, 1.5, 2, 3, 4, 5, 7, 10, and 15 days respectively after the transaction, and ultrathin sections were pre pared for examination with electron microscope.Results Axons started to separat e from the myelin sheath at day 0.5 after the transection, followed by rapid va cuolar degeneration. Since day 2, the myelin sheath folded and broke into fragme nts, and in the Schwann cells large cell membrane-bound myelin debris and many scattered small fragments could be seen to fuse with the lysosomes to form ACPa se reaction-positive autophagic vacuoles. Immature cells were occasionally seen in the endoneural space, appearing in large amount a week later. After day 7, the number of autophagic vacuoles began to diminish. In the entire course of the observation, macrophages containing autophagic vacuoles, were spotted only occa sionally.Conclusion The degenerated myelin debris are cleared mainly through t he mechanism of autophagy by the Schwann cells during regeneration of rat sciat ic nerve. Schwann cells dedifferentiate into Schwann cell precursors, which then proliferate and differentiate to take part in the regeneration of the nerves.