Embodiments of the present invention provide a self-interference cancellation method, a transceiver, and a communications device for a transmit/receive shared antenna. The method includes: in a self-interference channel measurement timeslot, transmitting a first reference signal on a transmit channel, and receiving a second reference signal on a reference signal receive channel, where the second reference signal is a reference signal obtained after the first reference signal passes through a self-interference signal transmission path; and performing channel estimation according to the first reference signal and the second reference signal to obtain description information of the self-interference transmission path.