Abstract: In this work, facile and green synthesis of Fe3O4/Ag Nanocomposite (NCs), is studied using pomegranate fruit bark extract as a natural reducing and capping agent. The properties of the synthesized Fe3O4/Ag NCs were characterized by advance techniques. For example; the high crystallinity and spherical shape with average size around 30 nm were confirmed by X-Ray powder Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques, respectively, as well as vibrating sample magnetometer (VSM) analysis shows high magnetism potential with saturation magnetization of 35 emu/g using. As a practical application the photocatalytic activity of synthesized NCs was evaluated on degradation of metronidazole (MNZ) in aqueous solution. The effect of three parameter including; conditions of MNZ, Fe3O4 /Ag NCs dosage and pH on degradation efficiency, were optimized. At the optimum condition the removal efficiency, degradation and COD, were achieved of 79.6% and 50.3%, respectively. In addition, the degradation kinetic and energy consumption was investigated and was also revealed in comparison to the similar photocatalytic degradation of MNZ reported.