Embodiments of the present invention provide an apparatus for self-interference cancellation. The apparatus includes: a first splitter, configured to perform splitting processing on a local oscillator signal generated by a local oscillator to separately transmit the local oscillator signal to an up-converter and a delayer; the up-converter, configured to perform up-conversion processing on a baseband transmit signal according to the local oscillator signal to generate a transmit signal; the delayer, configured to perform delaying processing on the local oscillator signal according to a preset target delay; a first down-converter, configured to perform, based on the local oscillator signal obtained after the delaying processing, down-conversion processing on a receive signal to acquire a baseband receive signal, and transmit the baseband receive signal to a self-interference canceller; and the self-interference canceller, configured to perform self-interference cancellation processing on the baseband receive signal.