Abstarct:   Abstract In this research, a magnetic nanocomposite modified with polyoxomextalate has been synthesized as a strong adsorbent for the removal of the antibiotic metronidazole (MNZ) from the Aqueous solution. And the physical and chemical properties of the adsorbent were analyzed by using FTIR, XRD, SEM, EDX, BET and TEM analyses. Activated biochar carbon is a suitable potential surface for using POM to modify the surface and adsorbent performance. Experiments showed that the removal efficiency of metronidazole increased significantly after modifying the adsorbent surface by polyoxomextalate (H3PW12O40) compared to magnetized adsorbent (MNP-BC). In order to study the effect of operating parameters such as solution pH, initial pollutant concentration, amount of adsorbent and contact time on metronidazole removal efficiency, experimental design using response surface method (RSM) was used by Design Expert software. The results showed that the removal efficiency of metronidazole under optimal conditions (pH= 1, initial concentration of metronidazole 5 mg/L, adsorbent amount 0.6 g/L and contact time 60 minutes) is 94.28%.The isotherm and kinetic studies showed that the adsorption process follows the Freundlich isotherm model and the pseudo second-order kinetic model. Also, the efficiency and reusability of the adsorbent in removing metronidazole was investigated and the results showed that after 4 cycles, its efficiency is more than 90%, which indicates the high potential and economy of this adsorbent.