The invention discloses an ultrahigh-frequency sensor and a local discharge detection device. The ultrahigh-frequency sensor comprises an insulating support, an antenna and short-circuit dowels. The antenna with curved surfaces is arranged on the insulating support; the short-circuit dowels are connected onto the antenna. The ultrahigh-frequency sensor and the partial discharge detection device have the advantages that the omni-directional property of the ultrahigh-frequency sensor can be improved; the performance of the ultrahigh-frequency sensor can be adjusted via the short-circuit dowels, so that working frequency bands of the ultrahigh-frequency sensor can be expanded and widened, the ultrahigh-frequency sensor is excellent in performance, and substation space orientation requirements can be met.