A network signal coupling and EMI protection circuit assembly includes a processing circuit installed in a circuit board and coupled between a voltage-mode network-on-chip at the circuit board and a network connector and drivable by a driving voltage from the voltage-mode network-on-chip to process network signals. The processing circuit includes opposing first connection end and second connection end, two-wire channels electrically connected between the first connection end and the second connection end, a coupling module and an EMI protection module installed in each two-wire channel for coupling network signals and removing noises. Each EMI protection module includes two capacitors having respective first ends thereof respectively connected to the two wires of the respective two-wire channel and respective opposite second ends thereof connected in series and grounded for filtering lower frequency part of resonant waves in the band during signal transmission to prevent electromagnetic interference and to enhance signal transmission stability.