Doped functional polymers, such as magnetic self‐healing polymers based on magnetic inorganic nanoparticles, have raised great attention and been applied in many fields recently due to their superior properties. However, the deficiency of interface compatibility between the inorganic nanoparticles and organic polymers, and the sedimentation and non‐uniform dispersion of the inorganic nanoparticles led to difficulties in the fabrication and development of doped functional polymer materials. In this work, we took magnetic doped self‐healing polymers as an example and proposed an accessible method to solve the problem. We prepared organic‐polymer‐coated Fe3O4 nanoparticles with high interface compatibility and then applied them to successfully synthesize magnetic self‐healing polymers. The average size of the resulting coated Fe3O4 nanoparticles was 8.82±1.09 nm, the practical saturation magnetization of the nanoparticles and the magnetic self‐healing polymers was 83.35, 24.29 emu/g, respectively. In addition, the self‐healing efficiency of the magnetic self‐healing polymers could reach 74.3% when healing for 1 hour and 78.4% when adding a magnetic field compared with 75.8% for the pure self‐healing polymers and 34.5% of magnetic polymers based on pure Fe3O4 nanoparticles. This work may offer a reference in fabricating doped functional polymers based on inorganic nanoparticles with high interface compatibility.