The present invention discloses a self-interference signal cancellation device. The device includes a first self-interference cancellation unit, configured to: obtain a first analog signal by coupling a transmit signal output by an analog transmit processing module; perform analog-to-digital conversion on the first analog signal, to obtain a first digital signal; perform interference reconstruction according to the first digital signal, to obtain a first digital interference cancellation signal; and cancel, according to the first digital interference cancellation signal, a self-interference signal included in a digital signal output by a first analog-to-digital conversion module, to obtain a first output signal, and output the first output signal to a digital receive processing module. In the present invention, after interference cancellation is performed by using the first digital interference cancellation signal and the digital signal output by the first analog-to-digital conversion module, a self-interference signal introduced during transmission can be canceled.