This application provides a full-duplex self-interference weakening method and a full-duplex self-interference weakening system. The full-duplex self-interference weakening method includes: separately receiving, by a first port of a dual-polarized receive antenna and a second port of the dual-polarized receive antenna, a signal sent by a transmit antenna; and adjusting and combining the signal received by the first port of the dual-polarized receive antenna and/or the signal received by the second port of the dual-polarized receive antenna, to weaken interference caused by the transmit antenna to the dual-polarized receive antenna. The full-duplex self-interference weakening method and the full-duplex self-interference weakening system provided in this application resolve a problem that a quantity of antennas and an antenna location are limited in an existing antenna interference cancelation method.