A power module with current rerouting across a printed circuit board (PCB) for decreasing electromagnetic interference and signal degradation is applied in an electronic device. The power module includes the PCB, a switch control chip, a switch circuit, a filtering circuit, a first switch, a second switch, and a control unit. The PCB includes a powered copper area, a first ground copper area, and a second ground copper area. When in the S3, S4, or S5 state and a voltage output terminal is disabled, the control unit turns off the first switch and turns on the second switch, to couple the powered copper area to the second ground copper area. When the voltage output terminal is enabled, the control unit reverses the on and off operations to enable the voltage output terminal to output a voltage.