The invention provides a method for preparing boron or boron-nitrogen doped graphene. The method comprises steps as follows: (1), magnesium powder, a solid carbon source and a boron or boron-nitrogen source which are well weighed are uniformly mixed, mixed powder is obtained, and the mass ratio of the magnesium powder, the solid carbon source and the boron or boron-nitrogen source in the mixed powder is (19.95-99):(40-79.95):(1-39.5); (2), the mixed powder obtained in the step (1) is subjected to a combustion synthesis reaction in a specific atmosphere, and boron or boron-nitrogen doped grapheme is obtained after a reaction product is purified. A substance containing boron or boron-nitrogen is adopted and serves as the boron or boron-nitrogen source, preparation and doping of the graphene are finished in one step, and the prepared boron or boron-nitrogen doped graphene has a complete laminated structure, good dispersion, high quality and a large effective specific surface area and has wide application prospects in nanocomposite materials, energy storage devices, catalysts and ferromagnetic devices.