Abstract: In this experiment, the Fe₃O₄ nanoparticles were prepared using hydrothermal method. The gold magnetic particles ( Fe₃O₄@ Au) were formed by the Fe₃O₄ nanoparticles combined with gold nanoparticles using self-assembly method based on the surface amino groups. Fe₃O₄@ Au was characterized based on the optimization of process. The results showed that gold nanoparticles prepared by grape skin extract with 1% concentration and the average particle size were 7 nm. The Fe₃O₄ functionalized with amino groups could be loaded with gold nanoparticles, the optimum process combination was as follows: the addition of Fe₃O₄ suspension was 2 m L, the temperature was 60 ℃, and the time was 60 min. Fe₃O₄@ Au, whose saturation magnetization was 61 emu/g, showed strong catalytic properties.