Iron oxide nanoparticles (IOXn) are unstable in aqueous solutions, which prevents their use in various applications. Because of this, it was proposed to treat the IOXn surface by employing a dispersant like sodium poly (naphthalene formaldehyde) sulfonate (PNS). In a single easy process, the (IPNS) were made by covering the IOXn with PNS. The material's structure, morphology, and magnetic properties were identified using XRD, TEM, Zeta potential, FTIR, HR-SEM, and a VSM. Due to its complex molecular structure and high anionic charge density, the polymeric dispersant (PNS) displays various characteristics. PNS successfully modifies the IOXn surface to create excellent colloidal electrostatic stability. At pH = 8, the zeta potential decreased from −13 to –23 mv. After the coating procedure, the crystalline structure changed into an amorphous one. The average particle size was decreased from 138 to 32 nm. In addition, there was a slight reduction in the magnetization saturation (Ms).