Objective To investigate the magnetic origin of Mn-doped SiC films from the atom level. Methods The films of Mndoped SiC were fabricated by radio frequency-magnetron sputtering. The structure, components and magnetic properties of films were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS) and physical property measuring system (PPMS), respectively. Results The analysis of crystal structure and composition showed that the structure of 3C-SiC was formed in the films after 1200 ℃ anneal, and with the increasing of Mn content, the characteristic peaks of 3C-SiC moved to lower angle. In 3% , 5% and 7% Mn-doped SiC films, the doping Mn atoms existed in the form of Mn2+ ions, but in 9% Mn-doped SiC film, the second phase of compound Mn4 Si7 appeared. The study of local structure of films showed that there were no Mn clusters or Mn-related oxides. The doped Mn atoms existed in the form of substitution for C sites in 3C-SiC lattice in 3% , 5% and 7% Mn-doped SiC films, and in 9% Mn-doped SiC film there was a coexistence of C substitution and compound Mn4 Si7 . The magnetic measurement by PPMS showed that the Mn-doped SiC films were ferromagnetic at room temperature, and the saturation magnetization increased with the increasing of Mn content. Conclusion The magnetism of films is intrinsic and relevant to the defects caused by Mn in the form of Mn2+ substituted for C in 3C-SiC lattice and is accorded with the bound magnetic polarons (BMP) mechanism accused by defects.