A signal cancellation method for a wireless communication system, carried out by a transmitter, the method comprises: splitting a signal to obtain a main channel signal transmitted on a main channel and an auxiliary channel signal transmitted on an auxiliary channel, performing digital domain channel characteristic matching processing on the main channel signal and the auxiliary channel signal respectively to obtain a main channel characteristic matched signal and an auxiliary channel characteristic matched signal, wherein channel characteristics of the main channel and the auxiliary channel are calculated, and the digital domain channel characteristic matching is executed according to the channel characteristics of the main channel and the auxiliary channel, wherein the digital domain channel characteristic matching processing adjusts the amplitude, phase and delay parameters of the main channel and the auxiliary channel so that the main channel signal and the auxiliary channel signal have a same amplitude and a same delay and opposite phases; and combining the main channel characteristic matched signal and the auxiliary channel characteristic matched signal and inputting the combined signal into a channel characteristic calculation control module for controlling the matching processing of the main channel signal and the auxiliary channel signal to carry out signal cancellation, the method being characterized in that: the main channel and the auxiliary channel share a local oscillator, and a spectrum density of a non-linear component generated on the auxiliary channel by a carrier signal energy filtered by a carrier suppression filter is over 10dB lower than a thermal bottom noise spectrum density. splitting a signal to obtain a main channel signal transmitted on a main channel and an auxiliary channel signal transmitted on an auxiliary channel, performing digital domain channel characteristic matching processing on the main channel signal and the auxiliary channel signal respectively to obtain a main channel characteristic matched signal and an auxiliary channel characteristic matched signal, wherein channel characteristics of the main channel and the auxiliary channel are calculated, and the digital domain channel characteristic matching is executed according to the channel characteristics of the main channel and the auxiliary channel, wherein the digital domain channel characteristic matching processing adjusts the amplitude, phase and delay parameters of the main channel and the auxiliary channel so that the main channel signal and the auxiliary channel signal have a same amplitude and a same delay and opposite phases; and combining the main channel characteristic matched signal and the auxiliary channel characteristic matched signal and inputting the combined signal into a channel characteristic calculation control module for controlling the matching processing of the main channel signal and the auxiliary channel signal to carry out signal cancellation, the method being characterized in that: the main channel and the auxiliary channel share a local oscillator, and a spectrum density of a non-linear component generated on the auxiliary channel by a carrier signal energy filtered by a carrier suppression filter is over 10dB lower than a thermal bottom noise spectrum density. the main channel and the auxiliary channel share a local oscillator, and a spectrum density of a non-linear component generated on the auxiliary channel by a carrier signal energy filtered by a carrier suppression filter is over 10dB lower than a thermal bottom noise spectrum density.