We report the effects of the O-2 introduction during electron irradiation assisted film growth on the structure and magnetic behavior of the graphene nanocrystallites embedded carbon (GNEC) films. It was found that although O-2 was introduced into the chamber during film deposition, there were nearly no oxygen atoms incorporated into the film. The introduced O-2 mainly had an effect on selectively removing the amorphous carbon (a-C) phase and gradually promoting the graphene nanocrystallite growth. Such effect brought about more graphene edges in the GNEC film, and then the saturation magnetization of the film M-s at 300 K increased from 0.10 emu/g to 0.28 emu/g. This research proposes an effective approach to enhance graphene-edge-induced carbon magnetism, providing fundamental basis for potential applications of graphene-based materials in magnetic devices.