We proposed a new way to synthesize a nanocomposite consisted of cementite Fe3C nanoparticles and amorphous carbon by radio frequency plasma-enhanced chemical vapor deposition. Transmission electron microscope images show the existence of nanometric dark grains(Fe3C) embedded in a light matrix(amorphous carbon) in the samples. X-ray photoelectron spectroscopy experiment exhibit that the chemical bonding state in the films corresponded to sp3/sp2 amorphous carbon, sp3 C―N(287.3 eV) and C1s in Fe3C(283.5 eV). With increasing deposition time, the ratio of amorphous carbon increased. The magnetic measurements show that the value of in-plane coercivity increased with increasing carbon matrix concentration(from about 6.56×103 A/m for film without carbon structures to approximately 2.77×104 and 5.81×104 A/m for nanocomposite films at room temperature and 10 K, respectively). The values of saturation magnetization for the synthesized nanocomposites were lower than that of the bulk Fe3C (140 Am2/kg). We proposed a new way to synthesize a nanocomposite consisted of cementite Fe3C nanoparticles and amorphous carbon by radio frequency plasma-enhanced chemical vapor deposition. Transmission electron microscope images show the existence of nanometric dark grains (Fe3C) embedded in a light matrix (amorphous carbon) in the samples. X-ray photoelectron spectroscopy experiment exhibit that the chemical bonding state in the ingetrated to sp3 / sp2 amorphous carbon, sp3 C-N (287.3 eV) and C1s in Fe3C (283.5 eV). With increasing deposition time, the ratio of amorphous carbon increased. The magnetic measurements show that the value of in-plane coercivity increased with increasing carbon matrix concentration (from about 6.56 × 10 3 A / m for film without carbon structures to approximately 2.77 × 10 4 and 5.81 × 10 4 A / m for nanocomposite films at room temperature and 10 K, respectively). The values ​​of saturation magnetization for the synthesized nanocomposites were lower than that of the bulk Fe3C (1 40 Am2 / kg).