A visible-light responsive Cu-Fe bimetallic amidoxime-modified polyacrylonitrile (denoted by Cu/Fe-AO-PAN) fiber was prepared using a facile and rapid microwave-assisted synthesis method. Several microscopic and spectroscopic techniques were adopted to characterize the morphology, structure, thermal and optical properties of the Cu/Fe-AO-PAN fiber. The results indicated that Cu(2+ )and Fe3+ ions were successfully coordinated with AO-PAN without causing distinct damage to the fiber and that chelation with metal ions extended the light absorption into the visible-light region. P-nitrophenol (PNP) was used to investigate the photocatalytic performance of the Cu/Fe-AO-PAN fiber in a photo-Fenton system under visible light irradiation. Various parameters that affected PNP removal were discussed, including the microwave heating temperature, irradiation time, Cu/ Fe molar ratio, and photo-Fenton reaction conditions, such as the pH, H2O2 concentration and fiber dosage. Under the optimal conditions, a PNP removal rate of approximately 100% was achieved within 150 min under visible light irradiation. The bimetallic Cu/Fe-AO-PAN exhibited improved pH tolerance, photocatalytic performance and stability compared to the monometallic Fe-AO-PAN fiber. In addition, a mechanism for PNP degradation induced by the Cu/Fe-AO-PAN fiber in the photo-Fenton system under visible light irradiation was proposed.