The invention provides a signal interference device and method. The device comprises a receiving link which is used for receiving an air signal and converting the air signal into a digital signal, andsending the digital signal to a programmable interference source module; the programmable interference source module which is used for carrying out de-synchronization processing on the digital signal, and generating a transmission modulation signal according to the de-synchronization processing result, and transmitting the transmitting modulating signal to a transmitting link; the transmitting link which is used for receiving the transmitting modulating signal, converting the emission modulating signal into a modulation interference signal, and radiating the modulation interference signal tothe air. According to the invention, the problem that a terminal signal interference device in the prior art is high in power requirement and relatively large in power consumption, and cannot completely block the terminal communication.