A graphene illuminator includes two electrodes, an accelerating electric field power supply, and several magnet sets, and further includes a graphene material used for providing free-electrons. The two electrodes are respectively disposed on both sides or at both ends of the graphene material, and meanwhile are both disposed on a plane where the graphene material is disposed; a positive electrode and a negative electrode of the accelerating electric field power supply are respectively connected to the two electrodes, to apply, in a first direction, an accelerating electric field to the graphene material; and the magnet sets are disposed on upper and lower sides of the plane where the graphene material is disposed, to generate a magnetic field perpendicular to the plane where the graphene material is disposed, and South poles and North poles of the magnet sets are arranged alternately to generate an alternating magnetic field in a second direction.