The traditional method for suppressing AM broadcast signal is to transmit high-power AM broadcast jamming signal to suppress AM broadcast signal. To achieve better effect of jamming signal, it is often necessary to increase the transmitter power, which creates more difficulty and cost. Based on the jamming suppression system model, this study proposes a new method of using Digital Radio Mondiale (DRM) jamming signals to suppress AM broadcast signal. The relationship equation of the input Jamming-to-Signal Ratio (JSR)and output JSR of DRM jamming signal is derived, and the effectiveness of DRM jamming signal and AM jamming signal on AM broadcast signal is compared. The experimental results reveal that given the same output JSR, the input JSR of the DRM jamming signal is only one third of the input JSR of the AM jamming signal, which indicatesthe jamming efficiency of DRM jamming signal is three times that of AM jamming signal.