An interference cancellation method and apparatus and also a filter are disclosed to cancel the interfering signals leaked to the receiving channel, and enable the receiving channel to suppress the transmitted signal. The method includes: dividing a transmitted signal into a first transmitted signal and a second transmitted signal, and then inputting the first transmitted signal into a first transmitting filter and inputting the second transmitted signal into a second transmitting filter symmetric to the first transmitting filter; adjusting the first interfering signal and the second interfering signal to make opposite phases of the signals; and combining the signals of opposite phases. The method provided herein can cancel the interfering signals leaked to the receiving channel, the receiving channel suppresses the transmitted signal effectively, and the interference caused by the transmitted signal onto the received signal is cancelled.