The invention discloses a spectral interference detection device and a spectral interference detection method. The device comprises a receiving antenna used for receiving spatial signals, a normal signal processing unit used for performing filtering and low noise amplification on normal signals and sending the normal signals to a radio frequency processing unit, an interference signal processing unit used for preprocessing interference signals and sending the interference signals to the radio frequency processing unit, the radio frequency processing unit used for performing radio frequency processing on the received normal signals and performing radio frequency processing on the preprocessed interference signals at free timeslots, a radio frequency sampling unit used for performing radio frequency sampling on the normal signals according to the input sampling clock, performing radio frequency sampling on the interference signals subjected to radio frequency processing at free timeslots and sending the interference signals subjected to radio frequency sampling to an interference signal detection unit, and the interference signal detection unit used for performing digital domain fast Fourier transform on the interference signals subjected to radio frequency sampling, performing frequency band recognition and acquiring a communication system of the interference signals.