In this study, magnetic biochar was successfully synthesized via one-step pyrolysis of FeCl3-loaded rice husk. Properties of the obtained magnetic biochar were determined by X-ray powder diffraction, SEM image, nitrogen adsorption isotherm, and vibrating sample magnetometer. The results revealed that magnetic Fe3O4 particles along with zero-valent iron particles were formed over biochar support at 600 C in 2 h. The magnetic biochar samples were subsequently utilized as oxidation catalysts for p-nitrophenol degradation by H2O2. Parameters including pH value, H2O2 concentration, biochar catalysts with different Fe-loaded contents were investigated. At high pH 6, 540 ppm H2O2 and 0.1 g magnetic biochar with 20 wt% Fe-loaded content, 99.8% p-nitrophenol could be removed after 90 min treatment. In addition, magnetic biochar particles could be removed from the treated solution by magnets easily. Overall, eco-friendly magnetic biochar can potentially be an effective catalyst for p-nitrophenol treatment in wastewater.