Abstract: A self-interference signal cancellation device and method are disclosed. A power divider divides a signal source into two paths, with one being connected to a transmit antenna and the other being connected to an input end of a self-interference signal reconstruction circuit. An output end of the self-interference signal reconstruction circuit is connected to a first input end of a combiner. An output end of a receive antenna is connected to a second input end of the combiner and a feedback regulating end of the self-interference signal reconstruction circuit, respectively. The transmit antenna and the receive antenna are arranged at different positions. According to the self-interference signal cancellation device of the present invention, by means of polarization isolation and separate arrangement between the transmit antenna and the receive antenna, high isolation between the antennas can be achieved, thereby reducing requirements for simulation elimination.