In this study, polyethylene terephthalate (PET) nanofibers are dipped into the extraction of pomegranate leaves (Punica granatum) in aqueous solution operated as a reducing agent to fabricate PET nanofibers with CuO nanoparticles, which are used later for the photocatalytic degradation methylene blue (MB) in aqueous solution. Scanning electron microscopy analysis is used to study the surface nanofiber morphology. UV-visible spectrophotometry is used to determine the concentration of (MB) after photodegradation. Photodegradation of (MB) in this study has shown that the degradation efficiency is affected by many factors like time, pH, and concentration. The results have proved that PET nanofibers/CuO nanoparticles acquire high photodegradation efficiency in a short time.