Abstarct: In this project, a new active photocatalyst called Poly-o-phenylenediamin/NiFe2O4/AgI nanocomposite was prepared with a suitable bandgap energy of 2.10eV. The PoPD nanostructures with spherical morphology were synthesized at a temperature of 118Co in concentrated acetic acid. Magnetic NiFe2O4 nanoparticles were synthesized under simple conditions on a polymer substrate, and the silver iodide (AgI) nanoparticles were immobilized to obtain the PoPD/NiFe2O4/AgI nanocomposite. This photocatalyst was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), UV-visible diffuse reflectance spectroscopy (DRS), surface area measurement analysis (BET), and magnetic analysis (VSM). The prepared photocatalyst was used for the degradation of organic dyes, including methylene blue, safranin, malachite green, crystal violet, as representative samples of organic pollutants found in nature, under visible light irradiation. The effects of various parameters such as time, concentration, amount of photocatalyst, and pH on the degradation of methylene blue dye were investigated. The results obtained from the degradation of methylene blue dye in an aqueous solution showed that the PoPD/NiFe2O4/AgI nanocomposite exhibited better photocatalytic performance compared to PoPD/NiFe2O4 and PoPD/AgI nanocomposites. A probable degradation mechanism was proposed by examining the influence of various factors. Furthermore, the stability of the photocatalyst was evaluated through multiple recycling stages.