An EMI noise shielding device applied to a power supply control system includes a first resistor with a terminal electrically coupled to a terminal of a second resistor to form an input terminal, a differential amplifier for receiving a feedback voltage (Vfb) signal containing a noise from the input terminal to perform a first filter process to generate a first node voltage (VA) signal, a signal converter for receiving the first node voltage (VA) signal to perform an analog-to-digital signal conversion process and a second filter process to generate a second node voltage (VB) signal, and a digital control circuit for receiving the second node voltage (VB) signal to perform a determination process and a third filter process to generate a third node voltage (VC) signal. Therefore, the noise signal contained in the feedback voltage (Vfb) signal can be filtered to maintain the normal operation of the power supply control system.