A method for reducing or eliminating an interference signal includes: coupling a transmission signal transmitted from a transmission antenna of a communication device so as to obtain a reference signal; adjusting a power and a phase of the reference signal, superimposing a cancellation signal obtained by the adjusting with a received signal received by a reception antenna of the communication device, and coupling the obtained superposition signal so as to obtain an acquisition signal; and repeating the adjusting until a voltage value of the acquisition signal is smaller than or equal to a historical minimum voltage value, the received signal including a useful signal and an interference signal formed by the transmission signal at the reception antenna; and determining the obtained superposition signal as a received signal for eliminating interference of the receive antenna, the received signal for eliminating interference of the receive antenna including the useful signal.