This application relates to the field of communications component technologies, and provides a band-stop filter and an electronic device. The band-stop filter includes: a waveguide transmission line, configured to transmit electromagnetic waves; and a plurality of dielectric resonance units, sequentially arranged along an extension track of the waveguide transmission line, and configured to be coupled to the waveguide transmission line, where the dielectric resonance units each include at least one dielectric resonator; the dielectric resonator includes a first dielectric block and a first conductive layer covering an outer surface of the first dielectric block; and a first surface of the first dielectric block has a blind hole, and the first conductive layer covers an inner surface of the blind hole; where a dielectric constant of a material that forms the first dielectric block is greater than 1.