The present invention discloses an EMI suppression device, comprising: a first transformer including a first circuit-end central tap to receive a first circuit signal from two first circuit-end signal taps, and a first cable-end central tap to receive a first cable signal from two first cable-end signal taps; a second transformer including a second circuit-end central tap to receive a second circuit signal from two second circuit-end signal taps, and a second cable-end central tap to receive a second cable signal from two second cable-end signal taps; a first circuit-end inductor coupled between the first circuit-end central tap and a system ground to reduce the common mode noise of the first circuit signal; and a second circuit-end inductor coupled between the second circuit-end central tap and the system ground to reduce the common mode noise of the second circuit signal. Said first and second circuit-end inductors operate separately.