The invention discloses a broadband antenna for measuring an electric field in spacecraft cabin. The antenna, instead of a traditional commercial electric field probe, with passive characteristics can realize broadband high-sensitivity frequency-domain electric field measurement. A feed joint can be connected with a spectrum analysis device to measure a weak electric field environment lower than 0.01V/m in the spacecraft cabin. The broadband antenna is compact in structure and portable, can be used in a narrow spacecraft cabin, can obtain distribution and size of the electric field in a random frequency point and in a random position in the cabin, and basically satisfies main emission and reception dot frequency requirements of a spacecraft wireless system.